CN117454997A - Ion trap chip parameter correction method and device, electronic equipment and media - Google Patents

Abstract

The present disclosure provides a method, apparatus, electronic device, computer readable storage medium and computer program product for ion trap chip parameter correction, and relates to the field of quantum computers, in particular to the technical field of ion trap chips. The implementation scheme is as follows: determining an intrinsic phonon frequency of a first ion in the ion trap chip; the following operations are performed a plurality of times: adjusting the power value of the laser and determining the equivalent amplitude of the laser irradiated to the first ion under the current power value; acquiring and setting a second pulse duration of the laser, and changing the frequency difference between two laser beams divided by the beam splitter by the laser to determine a second probability that the first ion is in an excited state under each frequency difference; determining a first phonon frequency based on a change in the second probability with the frequency difference; determining a difference between the first phonon frequency and the eigen-phonon frequency; and performing function fitting based on the corresponding relation between the equivalent amplitude and the corresponding difference value, so as to correct the phonon frequency under the corresponding equivalent amplitude based on the fitting function.

Description

Ion trap chip parameter correction method and device, electronic equipment and media

Technical field

The present disclosure relates to the field of quantum computers, in particular to the technical field of ion trap chips, and specifically to an ion trap chip parameter correction method, device, electronic equipment, computer-readable storage media and computer program products.

Background technique

Ion trap quantum computing is a computing method based on quantum mechanics. Its principle is to use the stable movement of ions in an electric field to process information as qubits. Through precise control of laser and microwave fields, quantum gate operations can be realized. thereby performing quantum computing. This method is currently considered one of the promising ways to achieve quantum computing.

The basic process of ion trap quantum computing is to use laser to cool ions, and form a binding potential in space through DC and alternating electric fields, so that the ions can rest at a point in the three-dimensional space, and then adjust the laser to achieve the desired effect between the ions. Quantum entanglement and manipulation. Since each ion can be abstracted into a qubit, many important tasks in quantum computing can be achieved by operating on them, such as quantum random walks, quantum simulations, and quantum searches. Ion trap quantum computing is highly controllable, can implement efficient quantum algorithms, and has broad application prospects. At the same time, ion trap quantum computing has very high requirements on experimental technology. It requires precise control of the position, energy level and interaction of ions, as well as high-precision measurement and control of ions.

Contents of the invention

The present disclosure provides an ion trap chip parameter correction method, device, electronic equipment, computer-readable storage medium and computer program product.

According to one aspect of the present disclosure, a method for modifying parameters of an ion trap chip is provided, including: determining the position of the first ion to be calibrated in the ion trap chip; obtaining and setting the initial power value of the laser so that the laser The equivalent amplitude after irradiation to the first ion is less than a first threshold; obtain and set the first pulse duration of the laser, and change the frequency difference between the two laser beams divided by the laser through the beam splitter, To determine the first probability that the first ion is in an excited state at each frequency difference; determine the intrinsic phonon frequency based on the change of the first probability with the frequency difference; perform the following operations N times, N is A positive integer greater than or equal to 2: adjust the power value of the laser, and determine the equivalent amplitude after the laser irradiates the first ion at the current power value; obtain and set the second pulse duration of the laser, and changing the frequency difference between the two laser beams that the laser is divided into by the beam splitter to determine the second probability that the first ion is in an excited state at each frequency difference; based on the second probability as described The change in frequency difference determines the first phonon frequency; determines the difference between the first phonon frequency and the intrinsic phonon frequency; and based on the equivalent amplitude and the corresponding difference Function fitting is performed on the corresponding relationship, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function.

According to another aspect of the present disclosure, an ion trap chip parameter correction device is provided, including: a first determination unit configured to determine the position of the first ion to be calibrated in the ion trap chip; an acquisition unit configured to acquire and set the initial power value of the laser so that the equivalent amplitude after the laser irradiates the first ion is less than the first threshold; a second determination unit configured to obtain and set the first pulse duration of the laser, And change the frequency difference between the two laser beams that the laser is divided into by the beam splitter to determine the first probability that the first ion is in the excited state at each frequency difference; the third determination unit is configured to be based on the The first probability changes with the frequency difference to determine the intrinsic phonon frequency; the execution unit is configured to perform the following operations N times, where N is a positive integer greater than or equal to 2: adjust the power value of the laser, and determine the current The equivalent amplitude after the laser irradiates the first ion at the power value; obtains and sets the second pulse duration of the laser, and changes the frequency between the two laser beams that the laser splits through the beam splitter difference to determine the second probability that the first ion is in an excited state at each frequency difference; determine the first phonon frequency based on the change of the second probability with the frequency difference; determine the first phonon frequency the difference between the sub-frequency and the intrinsic phonon frequency; and a correction unit configured to perform function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so that based on the fitting The obtained function corrects the phonon frequency at the corresponding equivalent amplitude.

According to another aspect of the present disclosure, an electronic device is provided, including: at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions that can be executed by at least one processor, and the instructions are at least One processor executes to enable at least one processor to execute the methods described in the present disclosure.

According to another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method described in the present disclosure.

According to another aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the method described in the present disclosure.

According to one or more embodiments of the present disclosure, the equivalent amplitude and the phonon frequency are correlated and calibrated, and the relationship between the corresponding equivalent amplitude and the difference is fitted, so that subsequent related acoustic measurements can be performed based on the difference. The phonon frequency is corrected to make the phonon frequency calibration more accurate, so that the corrected phonon frequency can be better suitable for ion trap experiments, which provides guarantee for the accuracy of experimental results.

It should be understood that what is described in this section is not intended to identify key or important features of the embodiments of the disclosure, nor is it intended to limit the scope of the disclosure. Other features of the present disclosure will become readily understood from the following description.

Description of the drawings

The drawings illustrate exemplary embodiments and constitute a part of the specification, and together with the written description, serve to explain exemplary implementations of the embodiments. The embodiments shown are for illustrative purposes only and do not limit the scope of the claims. Throughout the drawings, the same reference numbers refer to similar, but not necessarily identical, elements.

Figure 1 shows a flow chart of a method for modifying parameters of an ion trap chip according to an embodiment of the present disclosure;

2 shows a schematic diagram of determining ion positions by scanning laser and fluorescence imaging according to an embodiment of the present disclosure;

Figure 3 shows a schematic diagram of possible transitions after coupling of ions and phonons according to an embodiment of the present disclosure;

Figure 4 shows a schematic diagram of the blue sideband transition frequency sweep results and the baseline model theoretical fitting results according to an embodiment of the present disclosure;

Figure 5 shows a schematic diagram of determining phonon frequency based on frequency sweep experiments according to an embodiment of the present disclosure;

Figure 6 shows a structural block diagram of an ion trap chip parameter correction device according to an embodiment of the present disclosure; and

7 shows a structural block diagram of an exemplary electronic device that can be used to implement embodiments of the present disclosure.

Detailed ways

Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings, in which various details of the embodiments of the present disclosure are included to facilitate understanding and should be considered to be exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of the disclosure. Also, descriptions of well-known functions and constructions are omitted from the following description for clarity and conciseness.

In this disclosure, unless otherwise stated, the use of the terms “first”, “second”, etc. to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of these elements. Such terms are only used for Distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on contextual description, they may refer to different instances.

The terminology used in the description of the various described examples in this disclosure is for the purpose of describing the particular examples only and is not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element may be one or more. Furthermore, the term "and/or" as used in this disclosure encompasses any and all possible combinations of the listed items.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

So far, the various types of computers in use are based on classical physics as the theoretical basis for information processing, and are called traditional computers or classical computers. Classic information systems use binary data bits, which are physically easiest to implement, to store data or programs. Each binary data bit is represented by 0 or 1 and is called a bit or bit, as the smallest unit of information. Classical computers themselves have inevitable weaknesses: First, the most basic limitation of energy consumption in the calculation process. The minimum energy required for logic elements or storage units should be several times more than kT to avoid malfunction due to thermal expansion; the second is information entropy and heating energy consumption; the third is when the wiring density of computer chips is very high, according to the sea According to the Schenberg uncertainty relationship, when the uncertainty of the electron's position is small, the uncertainty of the momentum will be large. The electrons are no longer bound, and there will be quantum interference effects that can even destroy the performance of the chip.

Quantum computer is a type of physical device that follows the properties and laws of quantum mechanics to perform high-speed mathematical and logical operations, store and process quantum information. When a device processes and calculates quantum information and runs quantum algorithms, it is a quantum computer. Quantum computers follow the unique laws of quantum dynamics (especially quantum interference) to implement a new mode of information processing. For parallel processing of computing problems, quantum computers have an absolute advantage in speed compared to classical computers. The transformation implemented by a quantum computer on each superposition component is equivalent to a classical calculation. All these classical calculations are completed at the same time and superimposed according to a certain probability amplitude to give the output result of the quantum computer. This calculation is called quantum parallel computing. Quantum parallel processing greatly improves the efficiency of quantum computers, allowing them to complete tasks that cannot be completed by classical computers, such as factoring a large natural number. Quantum coherence is essentially exploited in all quantum ultrafast algorithms. Therefore, quantum parallel computing using quantum states instead of classical states can achieve computing speed and information processing capabilities that are unmatched by classical computers, while saving a large amount of computing resources.

In order to achieve high-performance ion trap quantum computing, parameter calibration of the ion trap system is crucial. In order to achieve high-fidelity quantum operations, researchers need to accurately calibrate the parameters of the ion trap system, including laser, phonon frequency, ion interaction, etc.

In ion trap quantum control, each ion in the trap represents a qubit, and the two internal states of the ion |↓>, |↑> can be expressed as the |0>, |1> states of the qubit. If two qubits need to be entangled, it is often necessary to guide the laser to illuminate two ions, and the two ions affected by the laser share the quantized phonon mode in the ion chain through charge Coulomb interaction. The equivalent Hamiltonian of such an experimental system is generally related to the parameters of the ion trap system, including laser frequency, amplitude and phase, phonon frequency, coupling strength, etc. Among them, in experiments, the adjustment of the equivalent Hamiltonian is generally achieved by adjusting the amplitude and phase of the laser pulse.

Therefore, in the quantum operation based on the ion trap system, the corresponding quantum operation can be realized based on the calibrated parameters. For example, the laser pulse is modulated based on more precise system parameters, and a more precise quantum gate is obtained by applying the laser pulse to the corresponding ion, thereby achieving more precise quantum computing operations based on the obtained quantum gate. Therefore, precise calibration of these parameters can improve the efficiency and accuracy of quantum operations in the ion trap, thereby improving the performance of ion trap quantum computing.

Among these parameters to be calibrated, the phonon frequency, the collective vibration mode of the ion trap, is particularly important. This is because in ion trap quantum computing, generating double-bit and multi-bit quantum gates requires precise operation and control of ions, and after each operation of the quantum circuit, it needs to be cooled and reset through phonons. These are all inseparable from the calibration of phonon frequency.

Theoretically, the phonon frequency corresponding to the collective vibration of ions in the ion trap is limited. The limitation in phonon frequency is caused by the Coulomb interaction between ions and the interaction between the positions of individual ions in the steady state. These interactions cause the collective vibrations of the ions to form specific frequency patterns that can be excited and tuned by precisely controlling the frequency and power of the laser. Therefore, the value of the phonon frequency corresponding to the collective vibration of ions in the ion trap can be used to precisely control the position and momentum of the ions. Operations in ion trap quantum computing often require precise control of the interactions between ions and the position of the ions, so the frequency of phonons in the ion trap needs to be precisely controlled. If there is an error in the phonon frequency calibration, the interaction between ions will lead to errors and noise in the calculation, thus affecting the accuracy and reliability of the entire calculation. Therefore, the accurate value of phonon frequency is one of the keys to ensuring high efficiency and accuracy in ion trap quantum computing.

In the ion trap experiment, the built ion trap system needs to be calibrated. A more accurate method is the Ramsey interference method. Ramsey interferometry is a measurement method based on quantum interference. By adjusting the free evolution time and observing the periodic changes of interference fringes, the energy difference between the internal energy levels of atoms or ions can be measured. In ion trap experiments, Ramsey interferometry can be used to measure the phonon frequency of ions. The specific operation method is: prepare an atom or ion from one energy level to another, then let it evolve freely for a period of time, and finally transfer it back to the prepared state. If two ions are at the same energy level, they will interfere and produce interference fringes; if two ions are at different energy levels, they will not interfere and no interference fringes will be produced. By adjusting the free evolution time, periodic changes in interference fringes can be observed. Based on the period of the interference fringe, the phonon frequency of the ion can be calculated.

However, the sensitivity of Ramsey interferometry is limited by the free evolution time. A shorter free evolution time will cause the visibility of the interference fringes to decrease, while a longer free evolution time will cause the periodic changes of the interference fringes to become less obvious. Ramsey interferometry requires high-precision laser and control systems and stable environmental conditions to obtain high-precision phonon frequency calibration results. Factors such as environmental noise or temperature changes may affect the experimental results. The Ramsey interferometry method requires multiple experiments to determine the phonon frequency, which increases the complexity and time-consuming of the experiment. In addition, the Ramsey interference method also requires the ion trap to have a high quality factor and a long life to ensure the stability of the interference fringes. This places certain requirements on the preparation and adjustment of ion traps.

Therefore, an ion trap chip parameter correction method is provided according to an embodiment of the present disclosure. Figure 1 shows a flow chart of a method for modifying parameters of an ion trap chip according to an embodiment of the present disclosure. As shown in Figure 1, the method 100 includes: determining the position of the first ion to be calibrated in the ion trap chip (step 110 ); obtain and set the initial power value of the laser so that the equivalent amplitude after the laser irradiates the first ion is less than the first threshold (step 120); obtain and set the first pulse duration of the laser, And change the frequency difference between the two laser beams that the laser is divided into by the beam splitter to determine the first probability that the first ion is in the excited state at each frequency difference (step 130); based on the first The probability changes with the frequency difference to determine the intrinsic phonon frequency (step 140); perform the following operations N times, where N is a positive integer greater than or equal to 2 (step 150): adjust the power value of the laser, and determine the current The equivalent amplitude of the laser after irradiating the first ion at the power value (step 1501); obtain and set the second pulse duration of the laser, and change the two laser beams that the laser splits through the beam splitter. frequency difference between each other to determine the second probability that the first ion is in an excited state at each frequency difference (step 1502); based on the change of the second probability with the frequency difference, determine the first phonon frequency (step 1503); determine the difference between the first phonon frequency and the intrinsic phonon frequency (step 1504); and based on the correspondence between the equivalent amplitude and the corresponding difference Function fitting is performed on the relationship, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function (step 160).

According to embodiments of the present disclosure, the equivalent amplitude and the phonon frequency are calibrated in correlation, and the relationship between the corresponding equivalent amplitude and the difference is fitted, so that the relevant phonon frequency can be subsequently corrected based on the difference. , making the phonon frequency calibration more accurate, making the corrected phonon frequency more suitable for ion trap experiments, and improving the accuracy of experimental results.

Due to the particularity of ion trap quantum computing, the ions as qubits float in a space of 10 to 100 μm above the ion trap chip. The distance between each two ions is related to the total number of ions, which is approximately 2 to 10 μm. The ions are generally unequal in distance, showing the characteristics of being dense in the middle and sparse on both sides. As the first step in ion trap quantum computing, it is first necessary to find the location of the qubit in space before subsequent quantum operations can be performed.

In some embodiments, determining the position of the first ion to be calibrated in the ion trap chip includes: changing the incident angle of the laser in a first preset range within a first preset step to determine through fluorescence imaging The position of the first ion.

In some examples, multiple ions in the ion trap can be scanned one by one by a scanning laser method to find the respective positions of the multiple ions. Scanning laser method, that is, if there are multiple ions in the ion trap, the laser can be used to scan the ions one by one. By changing the incident position of the laser beam and monitoring the fluorescence signal, the location of the ions can be found. When the laser beam coincides with an ion, the fluorescence signal changes significantly, determining the ion's position. 2 shows a schematic diagram of determining ion (qubit) position by scanning laser and fluorescence imaging according to an embodiment of the present disclosure.

Specifically, ion positions can be calibrated by fluorescence imaging and scanning laser beams. By cooling the ions with a laser and exciting them to a higher energy level, the ions emit fluorescent photons and de-excite back to their ground state. These fluorescent photons can be collected and detected by imaging systems such as optical microscopes and photomultiplier tubes or charge-coupled device (CCD) cameras. Since the fluorescence signal intensity is related to the degree of overlap between the ion position and the laser beam, the location of the ions can be found by processing and analyzing the collected fluorescence images.

It can be understood that the ions move slightly in their corresponding positions, so the determined position of the ions can also be called the central position, which is not limited here.

In some embodiments, obtaining and setting the initial power value of the laser so that the equivalent amplitude after the laser irradiates the first ions is less than a first threshold includes: adjusting the power value of the laser until the determined The equivalent amplitude is less than the first threshold and the power value corresponding to when the equivalent amplitude is less than the first threshold is determined as the initial power value: determining the first ion |g> state and |e> state to determine the frequency difference between the two laser beams split by the laser through the beam splitter based on the frequency difference; adjust the pulse duration of the laser, and determine the After the laser irradiates the first ion, the probability that the first ion is in the excited state; determines the third pulse duration corresponding to when the probability that the first ion is in the excited state is close to 1; and based on the third pulse duration Three pulse durations determine the equivalent amplitude of the laser after it strikes the first ion.

According to some embodiments, the equivalent amplitude Ω after the laser irradiates the first ions is determined based on the following formula:

Ω＝π/2τ

Where, τ is the third pulse duration.

In some examples, after determining the position of the first ion, the frequency difference of the two opposing laser beams can be modulated to be the same as the frequency difference between the first ion's internal states |g> state and |e> state, By continuously changing the pulse duration τ of the laser action, observe the change of the layout number of the first ion in the |e> state (excited state) with time until the first ion is in the |e> state after the laser pulse duration τ. The state probability is close to 1. In this way, the equivalent amplitude (ie, Rabi driving intensity) after the laser irradiates the first ion can be calibrated as Ω=π/2τ.

According to some embodiments, the first threshold includes 0.01 MHz.

It can be understood that the corresponding first threshold can be set according to the specific ion trap chip or actual needs, so that when the equivalent amplitude is less than the threshold, it can be assumed that the laser is difficult to couple the first ions and phonons, and the phonons frequency is close to its eigenfrequency.

According to some embodiments, the first pulse duration is greater than the second pulse duration.

It can be seen from the above that the equivalent amplitude (i.e., Rabi driving intensity) is inversely proportional to the laser pulse duration. Therefore, when the equivalent amplitude is small, a longer pulse duration τ can be selected to change the frequency difference between the two laser beams split by the laser through the beam splitter, and determine the first ion at each frequency difference. The first probability of being in an excited state, and then determining the intrinsic phonon frequency.

Since the Ramsey interference method is complicated to operate and consumes a lot of time, in an embodiment according to the present disclosure, a laser frequency sweep method is used to measure the phonon frequency of the ions. Specifically, by adjusting the frequency of the excitation signal (ie, the frequency difference between the two laser beams) with a laser sweeper and observing the changes in ion fluorescence, the layout number of ions in the excited state can be obtained.

In the example of determining the phonon frequency through a frequency sweep experiment, the frequency difference between the two laser beams split by the laser through the beam splitter will have an obvious peak when it approaches the phonon frequency. Therefore, the frequency difference corresponding to when the first probability peak occurs can be determined as the corresponding phonon frequency.

Similarly, according to some embodiments, determining the equivalent amplitude after the laser irradiates the first ion at the current power value includes: determining the frequency difference between the |g> state and the |e> state of the first ion , to determine the frequency difference between the two laser beams that the laser is divided into by the beam splitter based on the frequency difference; adjust the pulse duration of the laser, and determine that the laser is illuminated by the laser under each pulse duration. After the first ion is mentioned, the probability that the first ion is in the excited state; determine the fourth pulse duration corresponding to when the probability that the first ion is in the excited state is close to 1; and based on the fourth pulse duration The equivalent amplitude after the laser irradiates the first ions is determined.

According to some embodiments, the equivalent amplitude Ω after the laser irradiates the first ions is determined based on the following formula:

Ω＝π/2τ

Here, τ is the fourth pulse duration.

According to some embodiments, obtaining and setting the second pulse duration of the laser includes: setting the second pulse duration equal to the fourth pulse duration or close to the third pulse duration within a preset error range. Four pulse durations.

In some embodiments, after one ion (i.e., the first ion) is calibrated, the laser incident angle can be changed to address the next first ion to be calibrated, and the corresponding calibration process is repeated to complete the equivalent of the next ion. The amplitude is a function of the corresponding phonon frequency difference until all ions are calibrated.

In some examples, after obtaining the functional relationship between the fitted equivalent amplitude and the corresponding difference value, the values corresponding to the corresponding ions in the same or similar ion trap chip can be calculated based on the functional relationship. Quantum frequencies are corrected. For example, in some experiments, the eigenphonon frequency needs to be used, but the phonon frequency calibrated by the user is not its eigenfrequency. Since in the calibration of ion trap chip parameters, it is usually necessary to calibrate the equivalent amplitude and further calibrate the phonon frequency on this basis, the equivalent amplitude calibrated by the user and the phonon frequency obtained according to the embodiments of the present disclosure can be used. Functional relationship, determine the frequency difference corresponding to the equivalent amplitude calibrated by the user, and then subtract the frequency difference from the phonon frequency calibrated by the user to obtain the corresponding eigenfrequency. For another example, the manufacturer has given a corresponding phonon frequency, but in user experiments, due to the influence of the power, phase, amplitude, etc. of the laser used, there is a certain difference between the actual phonon frequency and the given phonon frequency. Therefore, the frequency difference corresponding to the equivalent amplitude calibrated by the user can be determined based on the equivalent amplitude calibrated in the user's experiment and the functional relationship obtained according to the embodiment of the present disclosure, and then the given phonon frequency Add this frequency difference to obtain the actual phonon frequency in the current user experiment.

It can be understood that the above-mentioned correction of the quantum frequencies corresponding to corresponding ions in the same or similar ion trap chips based on this functional relationship is only exemplary. In real physical experiments, users can obtain more accurate phonon frequencies at corresponding equivalent amplitudes based on this functional relationship based on their experimental needs, and there are no restrictions here.

In some frequency sweep experiments, when determining the phonon frequency based on the layout number (i.e., probability) of ions in the excited state, the frequency corresponding to the observed first blue sideband transition peak (i.e., the frequency that the laser is divided into by the beam splitter is usually The difference between the frequency (the frequency difference between the two laser beams) and the frequency corresponding to the main transition peak is regarded as the phonon frequency. However, only the blue sideband transition is considered at this time, while the impact of the main transition and the red sideband transition on the results is ignored; and only the two-level system is considered, that is, |g>|n> and |g>|n +1>, while actual ion trap systems have multiple energy levels.

Therefore, in some embodiments, the method according to the present disclosure further includes: determining a Hamiltonian expression of the quantum system corresponding to the first ion, so as to determine that the first ion is in a state based on the Hamiltonian expression. Probabilities of excited states. The Hamiltonian expression includes terms corresponding to blue sideband transitions, terms corresponding to red sideband transitions, and terms corresponding to main transitions.

As mentioned above, the difference between the first blue sideband transition frequency and the main transition frequency is usually read directly as the phonon frequency. But the actual situation is that only the blue sideband transition is considered, and the existence of the main transition and the red sideband transition is ignored. Therefore, there will be a deviation between the calibrated phonon frequency and the actual value.

In the embodiment according to the present disclosure, the effects of three transitions are considered at the same time, and the corresponding complete Hamiltonian is as follows:

Among them, j and k are ion and phonon indicators respectively, Ω _j is the equivalent Rabi driving frequency (ie equivalent amplitude), is the rising operator for the jth ion to transfer from |g> to |e>state,/> It represents the large detuning of the two laser beams that the laser is split into by the beam splitter, that is, the frequency difference between the two laser beams. It is also generally a variable that can be manipulated in frequency sweep experiments. η _j,k is the strength of the coupling between ions and phonons, a _k is the annihilation operator of phonons, ω _k is the frequency of phonons and is also the main object to be calibrated, and hc represents the conjugate term.

When η _j,k is small, the above Hamiltonian can be expanded and expressed in the following form:

When Δ _j =0, people generally ignore the following high-frequency terms, leaving only the Hamiltonian term, called the main transition. When Δ _j ≈ ω _k , the Hamiltonian approximately remains/> term, called the blue sideband transition. When Δ _j ≈ -ω _k , the Hamiltonian approximately remains/> term, called the red sideband transition. The three transitions above are generally all that people currently consider. The corresponding transition diagram is shown in Figure 3.

When only considering the blue sideband transition, after the evolution of the Hamiltonian of the interaction between the laser and the two-level system through time t, the probability of the ion in the |e> state can be easily calculated based on the corresponding Hamiltonian:

Among them, there is a deviation between the frequency sweep result and the actual situation, which is called "frequency drift", as shown in Figure 4.

In the above embodiment, the Hamiltonian expression used takes into account three transitions. Therefore, based on the Hamiltonian, the change of the layout number in the excited state with the laser frequency difference can be calculated. It should be noted that equipment (such as fluorescence detection equipment) for observing the layout number (probability) of ions in an excited state can be easily obtained. In the simulation experiment, the changes in the layout number of ions in the excited state under different laser parameters can be calculated based on the determined Hamiltonian. Therefore, by calculating the change of the excited state layout number with frequency, the three layout numbers of main red and blue |e>|n>, |e>|n-1>, |e>|n+1> and the total number can be recorded. The |e> state layout number is shown in Figure 5.

As mentioned above, in the above example of determining the phonon frequency through a frequency sweep experiment, the frequency difference corresponding to when the first probability peak occurs can be determined as the corresponding phonon frequency. In the example shown in Figure 5, when the first probability peak appears, it generally corresponds to the peak value corresponding to the blue sideband transition. Therefore, the frequency difference corresponding to the wave peak in the region where the frequency difference is greater than 0 (that is, the peak corresponding to the blue sideband transition) can be read as the corresponding phonon frequency.

In the above embodiment, the Hamiltonian expression retains the influence of the main transition, the red transition, and the blue transition. The calibration results are more consistent with the real experimental situation, and the calibrated parameters are closer to the real experimental parameters.

According to an embodiment of the present disclosure, as shown in Figure 6, an ion trap chip parameter correction device 600 is also provided, including: a first determination unit 610 configured to determine the first ion to be calibrated in the ion trap chip. position; the acquisition unit 620 is configured to acquire and set the initial power value of the laser, so that the equivalent amplitude after the laser irradiates the first ion is less than the first threshold; the second determination unit 630 is configured to acquire and set a first pulse duration of the laser, and changing the frequency difference between the two laser beams that the laser is split into by a beam splitter to determine a first probability that the first ion is in an excited state at each frequency difference ; The third determination unit 640 is configured to determine the intrinsic phonon frequency based on the change of the first probability with the frequency difference; the execution unit 650 is configured to perform the following operations N times, where N is a positive integer greater than or equal to 2 : Adjust the power value of the laser, and determine the equivalent amplitude after the laser irradiates the first ion at the current power value; obtain and set the second pulse duration of the laser, and change the laser pass the frequency difference between the two laser beams split by the beam splitter to determine the second probability that the first ion is in an excited state at each frequency difference; and based on the variation of the second probability with the frequency difference, Determine a first phonon frequency; determine a difference between the first phonon frequency and the intrinsic phonon frequency; and a correction unit 660 configured to be based on the equivalent amplitude and the corresponding difference. Function fitting is performed based on the corresponding relationship between the two, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function.

Here, the operations of the above-mentioned units 610 to 660 of the ion trap chip parameter correction device 600 are respectively similar to the operations of steps 110 to 160 described above, and will not be described again.

According to embodiments of the present disclosure, an electronic device, a readable storage medium, and a computer program product are also provided.

Referring to FIG. 7 , a structural block diagram of an electronic device 700 that may serve as a server or client of the present disclosure will now be described, which is an example of a hardware device that may be applied to aspects of the present disclosure. Electronic devices are intended to refer to various forms of digital electronic computing equipment, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices may also represent various forms of mobile devices, such as personal digital assistants, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are examples only and are not intended to limit implementations of the disclosure described and/or claimed herein.

As shown in FIG. 7 , the electronic device 700 includes a computing unit 701 that can perform calculations according to a computer program stored in a read-only memory (ROM) 702 or loaded from a storage unit 708 into a random access memory (RAM) 703 . Perform various appropriate actions and processing. In the RAM 703, various programs and data required for the operation of the electronic device 700 can also be stored. Computing unit 701, ROM 702 and RAM 703 are connected to each other via bus 704. An input/output (I/O) interface 705 is also connected to bus 704.

Multiple components in the electronic device 700 are connected to the I/O interface 705, including: an input unit 706, an output unit 707, a storage unit 708, and a communication unit 709. The input unit 706 may be any type of device capable of inputting information to the electronic device 700, the input unit 706 may receive input numeric or character information, and generate key signal input related to user settings and/or function control of the electronic device, and This may include, but is not limited to, a mouse, keyboard, touch screen, trackpad, trackball, joystick, microphone, and/or remote control. Output unit 707 may be any type of device capable of presenting information, and may include, but is not limited to, a display, speakers, video/audio output terminal, vibrator, and/or printer. The storage unit 708 may include, but is not limited to, a magnetic disk or an optical disk. The communication unit 709 allows the electronic device 700 to exchange information/data with other devices through a computer network such as the Internet and/or various telecommunications networks, and may include, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication transceiver and/or a chip Groups such as Bluetooth devices, 802.11 devices, WiFi devices, WiMax devices, cellular communications devices, and/or the like.

Computing unit 701 may be a variety of general and/or special purpose processing components having processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processing processor (DSP), and any appropriate processor, controller, microcontroller, etc. Computing unit 701 performs various methods and processes described above, such as method 100 . For example, in some embodiments, method 100 may be implemented as a computer software program tangibly embodied in a machine-readable medium, such as storage unit 708. In some embodiments, part or all of the computer program may be loaded and/or installed onto electronic device 700 via ROM 702 and/or communication unit 709 . When the computer program is loaded into RAM 703 and executed by computing unit 701, one or more steps of method 100 described above may be performed. Alternatively, in other embodiments, computing unit 701 may be configured to perform method 100 in any other suitable manner (eg, by means of firmware).

Various implementations of the systems and techniques described above may be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on a chip implemented in a system (SOC), complex programmable logic device (CPLD), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include implementation in one or more computer programs executable and/or interpreted on a programmable system including at least one programmable processor, the programmable processor The processor, which may be a special purpose or general purpose programmable processor, may receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device. An output device.

Program code for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that the program codes, when executed by the processor or controller, cause the functions specified in the flowcharts and/or block diagrams/ The operation is implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media would include one or more wire-based electrical connections, laptop disks, hard drives, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above.

To provide interaction with a user, the systems and techniques described herein may be implemented on a computer having a display device (eg, a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user ); and a keyboard and pointing device (eg, a mouse or a trackball) through which a user can provide input to the computer. Other kinds of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and may be provided in any form, including Acoustic input, voice input or tactile input) to receive input from the user.

The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., A user's computer having a graphical user interface or web browser through which the user can interact with implementations of the systems and technologies described herein), or including such backend components, middleware components, or any combination of front-end components in a computing system. The components of the system may be interconnected by any form or medium of digital data communication (eg, a communications network). Examples of communication networks include: local area network (LAN), wide area network (WAN), the Internet, and blockchain networks.

Computer systems may include clients and servers. Clients and servers are generally remote from each other and typically interact over a communications network. The relationship of client and server is created by computer programs running on corresponding computers and having a client-server relationship with each other. The server can be a cloud server, a distributed system server, or a server combined with a blockchain.

It should be understood that various forms of the process shown above may be used, with steps reordered, added or deleted. For example, each step described in the present disclosure can be executed in parallel, sequentially, or in a different order. As long as the desired results of the technical solution disclosed in the present disclosure can be achieved, there is no limitation here.

Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are only exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples. It is limited only by the granted claims and their equivalent scope. Various elements in the embodiments or examples may be omitted or replaced by equivalent elements thereof. Furthermore, the steps may be performed in a different order than described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as technology evolves, many elements described herein may be replaced by equivalent elements appearing after this disclosure.

Claims (19)

1. An ion trap chip parameter correction method, comprising:

Determining the position of a first ion to be calibrated in the ion trap chip;

acquiring and setting an initial power value of a laser so that the equivalent amplitude of the laser after irradiating the first ions is smaller than a first threshold value;

acquiring and setting a first pulse duration of the laser, and changing a frequency difference between two laser beams split by a beam splitter of the laser to determine a first probability that the first ion is in an excited state at each frequency difference;

determining an eigenphonon frequency based on a change in the first probability with the frequency difference;

the following operations are performed N times, N being a positive integer of 2 or more:

adjusting the power value of the laser, and determining the equivalent amplitude of the laser irradiated to the first ion under the current power value;

acquiring and setting a second pulse duration of the laser, and changing a frequency difference between two laser beams split by the laser through a beam splitter to determine a second probability that the first ions are in an excited state at each frequency difference;

determining a first phonon frequency based on a change in the second probability with the frequency difference;

determining a difference between the first phonon frequency and the eigenphonon frequency; and performing function fitting based on the corresponding relation between the equivalent amplitude and the corresponding difference value, so that the phonon frequency under the corresponding equivalent amplitude is corrected based on the function obtained by fitting.

2. The method of claim 1, wherein obtaining and setting an initial power value of a laser such that an equivalent amplitude of the laser after irradiating the first ions is less than a first threshold comprises:

adjusting the power value of the laser until the determined equivalent amplitude is less than a first threshold value and determining the power value corresponding to the equivalent amplitude being less than the first threshold value as an initial power value:

determining a frequency difference between the first ion g and e states to determine a frequency difference between two laser beams split by a beam splitter based on the frequency difference;

adjusting pulse durations of the laser and determining a probability that the first ion is in an excited state after irradiation of the first ion by the laser at each pulse duration;

determining a third pulse duration corresponding to when the probability of the first ion in the excited state is close to 1; and

an equivalent amplitude of the laser after irradiating the first ion is determined based on the third pulse duration.

3. The method of claim 1, wherein the first pulse duration is greater than the second pulse duration.

4. The method of claim 1, wherein the first threshold comprises 0.01MHz.

5. The method of claim 1, wherein determining the location of the first ion to be calibrated in the ion trap chip comprises: and changing the incident angle of the laser according to a first preset step length within a first preset range so as to determine the position of the first ion through fluorescence imaging.

6. The method of claim 1, further comprising: determining Hamiltonian amount representation of the quantum system corresponding to the first ion, determining each probability that the first ion is in an excited state based on the Hamiltonian amount representation,

the Hamiltonian representation comprises an item corresponding to a blue sideband transition, an item corresponding to a red sideband transition and an item corresponding to a main transition.

7. The method of claim 1, wherein determining an equivalent amplitude of the laser after irradiating the first ion at a current power value comprises:

determining a frequency difference between the first ion g and e states to determine a frequency difference between two laser beams split by a beam splitter based on the frequency difference;

adjusting pulse durations of the laser and determining a probability that the first ion is in an excited state after irradiation of the first ion by the laser at each pulse duration;

Determining a fourth pulse duration corresponding to when the probability of the first ion in the excited state is close to 1; and

an equivalent amplitude of the laser after irradiating the first ion is determined based on the fourth pulse duration.

8. The method of claim 7, wherein acquiring and setting the second pulse duration of the laser comprises: setting the second pulse duration equal to the fourth pulse duration or close to the fourth pulse duration within a preset error range.

9. The method of claim 2 or 7, wherein the equivalent amplitude Ω of the laser after irradiation with the first ion is determined based on the following formula:

Ω＝π/2τ

where τ is the corresponding pulse duration when the probability of the first ion being in the excited state is close to 1.

10. An ion trap chip parameter correction apparatus comprising:

a first determining unit configured to determine a position of a first ion to be calibrated in the ion trap chip;

an acquisition unit configured to acquire and set an initial power value of a laser so that an equivalent amplitude of the laser after irradiating the first ion is smaller than a first threshold;

A second determining unit configured to acquire and set a first pulse duration of the laser and change a frequency difference between two laser beams divided by a beam splitter by the laser to determine a first probability that the first ion is in an excited state at each frequency difference;

a third determination unit configured to determine an eigenphonon frequency based on a variation of the first probability with the frequency difference;

an execution unit configured to execute the following operations N times, N being a positive integer of 2 or more:

adjusting the power value of the laser, and determining the equivalent amplitude of the laser irradiated to the first ion under the current power value;

acquiring and setting a second pulse duration of the laser, and changing a frequency difference between two laser beams split by the laser through a beam splitter to determine a second probability that the first ions are in an excited state at each frequency difference;

determining a first phonon frequency based on a change in the second probability with the frequency difference;

determining a difference between the first phonon frequency and the eigenphonon frequency; and

and the correction unit is configured to perform function fitting based on the corresponding relation between the equivalent amplitude and the corresponding difference value, so that the phonon frequency under the corresponding equivalent amplitude is corrected based on the function obtained by fitting.

11. The apparatus of claim 10, wherein the acquisition unit comprises an adjustment subunit configured to: adjusting the power value of the laser until the determined equivalent amplitude is less than a first threshold value and determining the power value corresponding to the equivalent amplitude being less than the first threshold value as an initial power value:

determining a frequency difference between the first ion g and e states to determine a frequency difference between two laser beams split by a beam splitter based on the frequency difference;

adjusting pulse durations of the laser and determining a probability that the first ion is in an excited state after irradiation of the first ion by the laser at each pulse duration;

determining a third pulse duration corresponding to when the probability of the first ion in the excited state is close to 1; and

an equivalent amplitude of the laser after irradiating the first ion is determined based on the third pulse duration.

12. The apparatus of claim 10, wherein the first pulse duration is greater than the second pulse duration.

13. The apparatus of claim 10, wherein the first threshold comprises 0.01MHz.

14. The apparatus of claim 10, wherein the first determination unit comprises a determination subunit configured to: and changing the incident angle of the laser according to a first preset step length within a first preset range so as to determine the position of the first ion through fluorescence imaging.

15. The apparatus of claim 10, further comprising a fourth determination unit configured to:

determining Hamiltonian amount representation of the quantum system corresponding to the first ion, determining each probability that the first ion is in an excited state based on the Hamiltonian amount representation,

the Hamiltonian representation comprises an item corresponding to a blue sideband transition, an item corresponding to a red sideband transition and an item corresponding to a main transition.

16. The apparatus of claim 11, wherein the equivalent amplitude Ω of the laser after irradiation with the first ion is determined based on the following formula:

Ω＝π/2τ

where τ is the third pulse duration.

17. An electronic device, comprising:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein the method comprises the steps of

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-9.

18. A non-transitory computer readable storage medium storing computer instructions for causing the computer to perform the method of any one of claims 1-9.

19. A computer program product comprising a computer program, wherein the computer program, when executed by a processor, implements the method of any of claims 1-9.