CN115049063A - Method, system and device for rapidly reading and resetting superconducting quantum bit - Google Patents
Method, system and device for rapidly reading and resetting superconducting quantum bit Download PDFInfo
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Abstract
The invention discloses a superconducting quantum bit rapid reading and resetting device, method and system, wherein the device comprises: the device comprises a superconducting qubit module, a reading resonant cavity module, an adjustable coupling module and a reading transmission line module; the adjustable coupling module comprises a coupler unit and a coupling control line, and the coupling control line is independently arranged on the coupling unit; one end of the reading resonant cavity module is connected with the quantum bit unit, and the other end of the reading resonant cavity module is respectively connected with the coupler unit and the reading transmission line module. The coupling strength of the coupler is dynamically adjusted by adjusting a control signal of the coupling control line. Under the non-reading and non-resetting states, the superconducting qubit module has longer decoherence time and smaller coupling with the external environment; in a reset state, the decoherence coherence time of the superconducting qubit module is short, and rapid reset can be completed; in a reading state, photons in the reading resonant cavity module can be quickly leaked into the reading transmission line module, and quick reading is completed.
Description
Technical Field
The invention relates to the field of quantum computing, in particular to a superconducting quantum bit rapid reading and resetting device.
Background
Superconducting qubits are quantum state carriers consisting of josephson junctions and related superconducting quantum circuits, a way to implement qubits.
Reading of a superconducting qubit refers to the process of obtaining quantum state information stored by the qubit by applying a read pulse. A commonly used device for reading a superconducting qubit is to couple a reading transmission line to a reading resonant cavity via a fixed capacitor or inductor, while the reading resonant cavity is coupled to the superconducting qubit via the capacitor via the fixed capacitor. The state of the superconducting qubit affects the resonant frequency of the read resonant cavity, and the state information of the superconducting qubit can be obtained by measuring the microwave transmission property of the read transmission line near the resonant frequency of the read resonant cavity, which requires energy exchange between the read transmission line and the read resonant cavity.
Resetting of a superconducting qubit refers to the process of resetting the state of the superconducting qubit to its ground state. When a qubit has completed a logical operation or completed a quantum state read, its state is indeterminate. The state of a superconducting qubit often requires a reset to its ground state when the next quantum operation is performed. In general, this process is achieved by waiting a sufficiently long time, the time scale requirement being much larger than the decoherence time of the superconducting qubit. In the process, the superconducting qubit exchanges energy with the outside world, and the resetting of the quantum state is realized by dissipating the energy in the environment.
In order to accelerate the reading and resetting process of the superconducting qubit and increase the execution speed of the quantum circuit, it is required to increase the coupling strength between the superconducting qubit and the read resonant cavity and the external environment. However, this inevitably leads to a reduction in the decoherence time of the superconducting qubit and the read resonator, making it difficult to accomplish high fidelity quantum computing tasks.
On one hand, when the quantum logic gate operation is executed, the longer the decoherence time of the superconducting qubit is, the better the coupling of the superconducting qubit and the external environment is; on the other hand, in the resetting process of the superconducting qubit, the larger the coupling between the superconducting qubit and the external environment is, the shorter the decoherence time is, and the faster the resetting speed is. Meanwhile, in order to accelerate the quantum state reading of the superconducting qubit, it is required that photons in the reading resonant cavity leak into the transmission line as quickly as possible when the reading pulse is ended, and in the mainstream technology based on the non-adjustable coupling, these three requirements cannot be realized simultaneously, which has a huge disadvantage.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method, a system and a device for rapidly reading and resetting a superconducting quantum bit.
In order to solve the technical problem, the invention is solved by the following technical scheme:
a superconducting qubit fast reading and resetting device comprises a superconducting qubit module, a reading resonant cavity module, an adjustable coupling module and a reading transmission line module, wherein the reading resonant cavity module is coupled with the superconducting qubit module, the reading resonant cavity module is used for reading the state of the superconducting qubit module, and the reading transmission line module is used for transmitting a reading signal of the superconducting qubit module;
the adjustable coupling module comprises a coupler unit and a coupler control line arranged in the coupler unit, one end of the reading resonant cavity module is connected with the superconducting qubit module, and the other end of the reading resonant cavity module is respectively connected with the coupler unit and the reading transmission line module;
the coupling strength of the reading resonant cavity module and the external environment is adjusted by applying a control signal to a coupler control line, so that the speed of energy leakage of the reading resonant cavity module and the qubit module to the external environment is controlled, namely the decoherence coherent time of the reading resonant cavity and the superconducting qubit is controlled.
As an implementation, the adjusting the coupling strength of the read cavity module with the external environment by applying the control signal to the coupler control line comprises:
adjusting a control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read resonator module when the superconducting qubit module is in a non-read and non-reset state;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state.
As an implementation, the superconducting qubit module comprises at least one josephson junction, the frequency of the superconducting qubit module being tunable or non-tunable.
As an embodiment, the coupler unit comprises at least one josephson junction, the equivalent inductance value of which is adjusted by applying a control signal to a coupler control line.
As one possible embodiment, the read cavity module is a distributed transmission line type cavity.
As an implementation, the superconducting qubit module further comprises a first capacitive unit connected in parallel with the superconducting qubit unit.
As an implementation, the adjustable coupling module includes a second capacitance unit, and the second capacitance unit is connected in parallel with the coupler unit.
As an implementation manner, the capacitor further comprises a third capacitor unit, a fourth capacitor unit and a fifth capacitor unit;
one end of the third capacitor unit is coupled to the superconducting qubit module, the other end of the third capacitor unit is coupled to one end of the reading resonant cavity module, the other end of the reading resonant cavity module is coupled to one end of the fourth capacitor unit, the other end of the fourth capacitor unit is respectively coupled to one end of the fifth capacitor unit and one end of the adjustable coupling module, and the other end of the fifth capacitor unit is connected to the reading transmission line module.
As an implementation manner, the inductor further comprises a third inductor unit, a fourth inductor unit and a fifth inductor unit;
one end of the third inductance unit is coupled to the superconducting qubit module, the other end of the third inductance unit is coupled to one end of the reading resonant cavity module, the other end of the reading resonant cavity module is coupled to one end of the fourth inductance unit, the other end of the fourth inductance unit is respectively coupled to one end of the fifth inductance unit and one end of the adjustable coupling module, and the other end of the fifth inductance unit is connected to the reading transmission line module.
A superconducting qubit fast read and reset method, comprising the steps of:
adjusting the intensity of a control signal applied to a coupler control line to change the coupling intensity of the reading resonant cavity module and the external environment;
obtaining the relation between the control signal intensity and the decoherence time of the reading resonant cavity module and the relation between the control signal intensity and the decoherence time of the superconducting qubit module;
adjusting a control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read resonator module when the superconducting qubit module is in a non-read and non-reset state;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state.
A computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the method and steps as set forth above.
A superconducting qubit fast read and reset system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, the processor implementing the methods and steps as described above when executing the computer program.
A superconducting qubit fast read and reset system includes the above-described superconducting qubit fast read and reset device.
Due to the adoption of the technical scheme, the invention has the remarkable technical effects that:
by the device, the method and the system, the adjustable coupling between the superconducting qubit module reading resonant cavity module and the reading transmission line module is realized. The coupling strength between the reading resonant cavity module and the external environment is adjusted by applying a control signal to the coupler control line, so that the adjustment of the superconducting quantum bit decoherence time and the reading resonant cavity decoherence time is realized. Through dynamic regulation and control of the coupler unit, the superconducting qubit module has longer decoherence time and smaller coupling with the external environment in the non-reading and non-resetting states; in a reset state, the decoherence coherence time of the superconducting qubit module is short, and rapid reset can be completed; in a reading state, photons in the reading resonant cavity module can be quickly leaked into the reading transmission line module, and quick reading is completed. The three points cannot be realized simultaneously in the main technology of the non-adjustable coupling.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of the overall structure of the apparatus of the present invention;
FIG. 2 is a schematic diagram of an equivalent circuit of the apparatus of the present invention;
fig. 3 is an effect diagram of the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples, which are illustrative of the present invention and are not to be construed as being limited thereto.
The invention realizes the adjustable coupling between the superconducting quantum bit module-reading resonant cavity module and the reading line module, namely, an adjustable coupler containing a Josephson junction is added between the reading resonant cavity module and the reading transmission line module.
Example 1:
a superconducting qubit fast reading and resetting device is shown in figure 1, and comprises a superconducting qubit module, a reading resonant cavity module, an adjustable coupling module and a reading transmission line module, wherein the reading resonant cavity module is coupled with the superconducting qubit module, the reading resonant cavity module is used for reading the state of the superconducting qubit module, and the reading transmission line module is used for transmitting a reading signal of the superconducting qubit module;
the adjustable coupling module comprises a coupler unit and a coupler control line arranged in the coupler unit, one end of the reading resonant cavity module is connected with the superconducting qubit module, and the other end of the reading resonant cavity module is respectively connected with the coupler unit and the reading transmission line module;
and applying a control signal to a coupler control line of the coupler unit to adjust the coupling strength of the reading resonant cavity and the external environment based on the state of the superconducting qubit module, and further controlling the phase-reversing coherence time of the reading resonant cavity module and the superconducting qubit module. In this embodiment, the decoherence time includes an energy relaxation time and a decoherence time, and the adjustment of the decoherence time of the superconducting qubit and the adjustment of the decoherence time of the read resonator are realized by applying a control signal to the coupler control line and adjusting the coupling strength between the read resonator module and the external environment.
In one embodiment, in particular, when the superconducting qubit module is in the non-read and non-reset states, adjusting the control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read cavity module;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state. In this embodiment, referring to fig. 3, the magnetic flux and the decoherence time satisfy a certain rule, and the superconducting qubit module has several forms when reading the 0 state and the 1 state of the superconducting qubit module read by the resonant cavity module: the invention provides a method for resetting, reading, non-resetting and non-reading a superconducting quantum bit module, which aims to quickly reset and read the superconducting quantum bit module, and when the superconducting quantum bit module is not read and not reset, a control signal module of a coupler is adjusted to the intensity of longer decoherence time of the superconducting quantum bit module and the reading resonant cavity module; when the state of the superconducting qubit module is read, the control signal of the coupler is adjusted to the state that the decoherence time of the superconducting qubit module is longer, and the intensity of the resonant cavity with shorter decoherence time is read, so that the superconducting qubit is quickly read; when the state of the superconducting qubit module is reset, the control signal of the coupler is adjusted to a position where the decoherence coherence time of the superconducting qubit module is short, so that the superconducting qubit module is reset quickly.
Referring to fig. 3, according to the rule of the curve, in order to realize fast reading, a control signal of a control line of a coupler needs to be adjusted to a position where the decoherence time of the superconducting qubit module is longer and the intensity of the resonant cavity with shorter decoherence time is read, and the position is a magnetic flux corresponding to a position where the curve change rate is relatively stable, so that fast reading of the superconducting qubit can be realized. In order to realize the rapid reset, the control signal of the coupler control line needs to be adjusted to a position with short decoherence time of the superconducting qubit module, the position is the magnetic flux corresponding to the position with the maximum curve change rate, the rapid reset of the superconducting qubit module can be realized, and the positions corresponding to the rest curves are in the adjustment range during non-reading and non-resetting. In the whole process, whether the superconducting qubit module is reset, read, not reset and not read is further determined, and the coupler control line is adjusted through the control signal based on the model of the magnetic flux and the decoherence coherent time after determining which forms the superconducting qubit module is in, so that the superconducting qubit module is quickly reset and read. Since the length of the decoherence time is different in each stage, the decoherence time can be distinguished according to different forms, namely the first decoherence time, the third decoherence time, the fifth decoherence time, the second decoherence time and the fourth decoherence time.
In one embodiment, the superconducting qubit module comprises at least one josephson junction. Of course, in other embodiments, there may be 2, 3 or other numbers, and in short, one or more may be used. In this embodiment, the superconducting qubit module is a Transmon qubit containing two josephson junctions. The superconducting qubit module further includes a first capacitive unit in parallel with the josephson junction. While the frequency of the superconducting qubit module may or may not be tunable.
In addition, in other embodiments, the superconducting qubit module further includes a first capacitive unit connected in parallel with the superconducting qubit unit.
Specifically, the coupler unit includes at least one josephson junction, in a parallel relationship when the josephson junctions are two or more, and an equivalent inductance value of the josephson junction is adjusted by applying a control signal to a coupler control line. Of course, in other embodiments, there may be 3, 4, or other numbers, and in short, one or more may be implemented. Additionally, in other embodiments, the adjustable coupling module further comprises a second capacitive unit connected in parallel with the josephson junction of the coupler unit.
In one embodiment, the read cavity module is a distributed transmission line cavity. The transmission line type resonator uses a lambda/4 resonator. The embodiment of the invention mainly aims at the situation that the reading resonant cavity is a transmission line type resonant cavity, but the content can be easily expanded to other situations that the reading resonant cavity is an LC resonator under a lumped model and the like.
In one embodiment, the capacitor further comprises a third capacitor unit, a fourth capacitor unit and a fifth capacitor unit; one end of the third capacitor unit is coupled to the superconducting qubit module, the other end of the third capacitor unit is coupled to one end of the reading resonant cavity module, the other end of the reading resonant cavity module is coupled to one end of the fourth capacitor unit, the other end of the fourth capacitor unit is respectively coupled to one end of the fifth capacitor unit and one end of the adjustable coupling module, and the other end of the fifth capacitor unit is connected to the reading transmission line module. Of course, in an actual operation process, the third capacitor unit, the fourth capacitor unit, and the fifth capacitor unit in this embodiment may be replaced with inductor units, and the connection manner may refer to the connection manner between each capacitor unit and other modules in this embodiment.
Example 2:
the device can realize a superconducting quantum bit rapid reading and resetting method, and comprises the following steps:
s100, adjusting the intensity of a control signal applied to a coupler control line to change the coupling intensity of the reading resonant cavity module and an external environment;
s200, obtaining the relation between the control signal intensity and the decoherence time of the reading resonant cavity module and the relation between the control signal intensity and the decoherence time of the superconducting qubit module;
adjusting a control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read resonator module when the superconducting qubit module is in a non-read and non-reset state;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state.
In the method, when the state of the superconducting qubit module is in a non-reading state and a non-resetting state, a control signal module of a coupler is adjusted to the intensity of longer decoherence time of the superconducting qubit module and a reading resonant cavity module; when the state of the superconducting qubit module is read, the control signal of the coupler is adjusted to the state that the decoherence time of the superconducting qubit module is longer, and the intensity of the resonant cavity with shorter decoherence time is read, so that the superconducting qubit is quickly read; when the state of the superconducting qubit module is reset, the control signal of the coupler is adjusted to a position where the decoherence coherence time of the superconducting qubit module is short, so that the superconducting qubit module is reset quickly.
To further illustrate the feasibility of the present invention, specific design forms are described below.
Fig. 1 shows an embodiment of the apparatus of the present invention, and as shown in fig. 1, the transmission line type resonant cavity uses a λ/4 resonant cavity, the superconducting qubit module is a Transmon qubit structure including two josephson junctions, the adjustable coupling module includes a coupler unit and a flux control line disposed inside the coupler unit, the coupler unit includes two josephson junctions, the two josephson junctions are connected in parallel, and the transmission line coupling SQUID circuit includes two parallel josephson junctions, a capacitor, and an independent flux control line. Impedance matching is performed at the output of the read module, and in this embodiment, the matched equivalent resistance is 50 ohms, but other embodiments may use other data.
The following calculation procedure is to calculate the decoherence time, and the data can illustrate the function of the device of the present invention to control the decoherence time through the adjustment of the adjustable coupling unit in the adjustable coupling module. Suppose the characteristic impedance of the read cavity module is Z r Reading the total impedance Z of the resonant cavity module if the length of the transmission line of the resonant cavity module is l, the propagation constant is beta and the attenuation constant is alpha in Is composed of
Z in ＝Z r tanh(α+jβ)l
Assume that the input at point A in FIG. 1 is Ae iωt Incident voltage V of in The output voltage V after being output by the read resonant cavity module 1 Assuming that the transmission line reflectivity of the read resonant cavity module is r, and assuming that the voltage transmittance on the equivalent infinite resistance of the read transmission line module is t, kirchhoff's theorem can obtain:
I＝(V in -V 1 )/Z in ；
V 1 ＝(1-r)V in ；
t＝(I-I 1 )Z ext /A
the equivalent inductance of the Josephson junction in the adjustable coupling module is directly determined by the magnetic flux of the coupler control line in the coupler unit, provided that the critical current of the Josephson junction is I c External magnetic field of phi and magnetic flux quantum phi 0 The value of (d) is h/2e, the following relationship holds:
and finally obtaining a change curve of the transmissivity t along with the magnetic field applied by the adjustable coupling module according to the formula.
Based on the transmittance T, the transmittance T and the decoherence time T are also required 1 The following relationships are derived to explain the effect of the present application, if:
reading incident power flow P of resonant cavity in Is A 2 /2Z r
Reading the dissipated power flow P of the resonant cavity loss Is t | 2 A 2 /2Z ext
The quality factor Q of the read cavity is
The time required by the energy attenuation to be 1/e is taken as the decoherence time T 1 Then the coherent time T is exited 1 Is calculated by the formula
The relation between the decoherence time and the applied magnetic field of the adjustable coupling module can be obtained through the formula. Of course, in a similar way, T of qubit can also be obtained 1 In addition, T of the quantum bit can be calculated by the following simple method 1
Wherein C is q Z is the capacitance in the qubit and the total external impedance of the superconducting qubit module transmission.
In a specific embodiment, the frequency of the superconducting qubit module is 6.5GHz, the frequency of the reading resonant cavity module is 5.0GHz, and the third capacitance unit C κ A fourth capacitor unit C 1 And a fifth capacitor unit C 2 Respectively, ofThe curves of the decoherence time of the superconducting qubit module and the decoherence time of the reading resonant cavity module, which are calculated respectively for 4.3fF, 2.4fF and 2.4fF, and the variation of the decoherence time of the reading resonant cavity module with the magnetic flux applied by the adjustable coupling module are shown in fig. 3.
Therefore, when the magnetic field is in a non-reading and non-resetting state, the magnetic flux is adjusted to a working point with longer decoherence time of the reading resonant cavity and longer decoherence time of the superconducting quantum bit, so that high-precision quantum logic operation is realized; in the resetting process of the superconducting qubit, the magnetic flux is adjusted to a working point with short decoherence time of the reading resonant cavity and short decoherence time of the superconducting qubit so as to accelerate the resetting speed of the quantum state; in the reading process of the superconducting qubit, the magnetic flux is adjusted to a working point with short decoherence time of the reading resonant cavity and long decoherence time of the superconducting qubit, so as to realize the fast reading of the quantum state.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (13)
1. A superconducting qubit fast reading and resetting device is characterized by comprising a superconducting qubit module, a reading resonant cavity module, an adjustable coupling module and a reading transmission line module, wherein the reading resonant cavity module is coupled with the superconducting qubit module and used for reading the state of the superconducting qubit module, and the reading transmission line module is used for transmitting a reading signal of the superconducting qubit module;
the adjustable coupling module comprises a coupler unit and a coupler control line arranged in the coupler unit, one end of the reading resonant cavity module is connected with the superconducting qubit module, and the other end of the reading resonant cavity module is respectively connected with the coupler unit and the reading transmission line module;
the coupling strength of the reading resonant cavity module and the external environment is adjusted by applying a control signal to a coupler control line, so that the speed of energy leakage of the reading resonant cavity module and the qubit module to the external environment is controlled, namely the decoherence coherent time of the reading resonant cavity module and the superconducting qubit module is controlled.
2. The superconducting qubit fast read and reset device of claim 1 wherein adjusting the coupling strength of the read resonator module to the external environment by applying a control signal to a coupler control line comprises:
adjusting a control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read resonator module when the superconducting qubit module is in a non-read and non-reset state;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state.
3. The superconducting qubit fast read and reset device of claim 1 wherein the superconducting qubit module comprises at least one josephson junction, the superconducting qubit module being frequency tunable or non-tunable.
4. The superconducting qubit fast read and reset device of claim 1 wherein the coupler unit comprises at least one josephson junction, an equivalent inductance value of the josephson junction being adjusted by applying a control signal to a coupler control line.
5. The apparatus of claim 1, wherein the read cavity module is a distributed transmission line cavity.
6. The superconducting qubit fast read and reset device of claim 1 wherein the superconducting qubit module further comprises a first capacitive unit in parallel with the superconducting qubit unit.
7. The superconducting qubit fast read and reset device of claim 1 wherein the tunable coupling module comprises a second capacitive unit in parallel with the coupler unit.
8. The superconducting qubit fast read and reset device of claim 1 further comprising a third capacitive unit, a fourth capacitive unit, and a fifth capacitive unit;
one end of the third capacitor unit is coupled to the superconducting qubit module, the other end of the third capacitor unit is coupled to one end of the reading resonant cavity module, the other end of the reading resonant cavity module is coupled to one end of the fourth capacitor unit, the other end of the fourth capacitor unit is respectively coupled to one end of the fifth capacitor unit and one end of the adjustable coupling module, and the other end of the fifth capacitor unit is connected to the reading transmission line module.
9. The apparatus of claim 1, further comprising a third inductor unit, a fourth inductor unit, and a fifth inductor unit;
one end of the third inductance unit is coupled to the superconducting qubit module, the other end of the third inductance unit is coupled to one end of the reading resonant cavity module, the other end of the reading resonant cavity module is coupled to one end of the fourth inductance unit, the other end of the fourth inductance unit is respectively coupled to one end of the fifth inductance unit and one end of the adjustable coupling module, and the other end of the fifth inductance unit is connected to the reading transmission line module.
10. A superconducting qubit fast read and reset method, comprising the steps of:
adjusting the intensity of a control signal applied to a coupler control line to change the coupling intensity of the reading resonant cavity module and the external environment;
obtaining the relation between the control signal intensity and the decoherence time of the reading resonant cavity module and the relation between the control signal intensity and the decoherence time of the superconducting qubit module;
adjusting a control signal applied to the coupler control line to an intensity corresponding to a first decoherence time of the superconducting qubit module and a second decoherence time of the read resonator module when the superconducting qubit module is in a non-read and non-reset state;
when the state of the superconducting qubit module is read, adjusting the intensity of a control signal applied to the coupler control line to the intensity corresponding to the third decoherence coherence time of the superconducting qubit module and the fourth decoherence coherence time of the reading resonant cavity module, and realizing the rapid resetting of the superconducting qubit module;
when the state of the superconducting qubit module is reset, adjusting the control signal applied to the coupler control line to the intensity corresponding to the fifth decoherence coherent time of the superconducting qubit module, so as to realize the rapid reset of the superconducting qubit module;
the first decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is in the non-reading state and the non-resetting state, the third decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is read, the fifth decoherence time is the decoherence time corresponding to the situation that the superconducting qubit module is reset, and the second decoherence time and the fourth decoherence time are the decoherence time corresponding to the situation that the reading resonant cavity module is in the non-reading state and the non-resetting state and the reading state.
11. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the method and steps of claim 10.
12. A superconducting qubit fast read and reset system comprising a memory, a processor, and a computer program stored in the memory and executed on the processor, wherein the processor implements the method and steps of claim 10 when executing the computer program.
13. A superconducting qubit fast read and reset system comprising the superconducting qubit fast read and reset device of any of claims 1 to 9.
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| CN116306458A (en) * | 2023-02-08 | 2023-06-23 | 北京百度网讯科技有限公司 | Quality factor determining method, device, equipment and storage medium |
| WO2024093319A1 (en) * | 2022-10-31 | 2024-05-10 | 华为技术有限公司 | Superconducting quantum bit read-out device, superconducting quantum chip and quantum computer |
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| WO2024093319A1 (en) * | 2022-10-31 | 2024-05-10 | 华为技术有限公司 | Superconducting quantum bit read-out device, superconducting quantum chip and quantum computer |
| CN116306458A (en) * | 2023-02-08 | 2023-06-23 | 北京百度网讯科技有限公司 | Quality factor determining method, device, equipment and storage medium |
| CN116306458B (en) * | 2023-02-08 | 2024-01-02 | 北京百度网讯科技有限公司 | Quality factor determining method, device, equipment and storage medium |
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