DE102022207843A1 - Integrated circuit for a quantum computer, as well as quantum computers and methods for operating an integrated circuit - Google Patents

Abstract

The invention relates to an integrated circuit (1) for a quantum computer (2), comprising: - an optical input (13), which is designed to receive an optical transmission signal (9), - a transformation device (14), which is used to generate an electrical Signal (15) is designed depending on the optical transmission signal (9), - a coupling device (19) which is used to couple the electrical signal (15) into a quantum bit unit (4) which has at least one quantum bit (5), and for coupling out an electrical control signal (22), which is based on the electrical signal (15) and with which a state of the at least one quantum bit (5) is characterized, is formed from the quantum bit unit (4), and - an electrical output ( 24), which is designed to provide the electrical control signal (22). Furthermore, the invention relates to a quantum computer (2) and a method.

Description

The invention relates to an integrated circuit for a quantum computer.

The invention further relates to a quantum computer with at least one integrated circuit and a central electronic computing device.

The invention also relates to a method for operating an integrated circuit.

For example, the reveals US 2021/0232962 A1 a gate with a first control qubit coupled to a first target qubit and a second gate with a second control qubit coupled to a second target qubit and the first control qubit. A control circuit for performing operations including first and second iterations is also provided.

Furthermore, the reveals US 11,195,117 B2 an architecture of a quantum computer. For this purpose, the architecture is designed in such a way that a large number of qubits can be used in the quantum computer.

Furthermore, the reveals US 2021/0342729 A1 also an architecture for a quantum processor. For this purpose, different quantum processor chips can be provided; each of these quantum processor chips can have a large number of qubits. Furthermore, a coupling unit can be provided here in order to be able to connect or couple the various qubits to one another.

An object of the present invention is to provide an integrated circuit so that a quantum computer can be manufactured with smaller space requirements and lower costs.

This task is solved by an integrated circuit, a quantum computer and a method according to the independent patent claims. Useful further training results from the dependent patent claims.

• - einen optischen Eingang, welcher zum Empfangen eines optischen Übertragungssignals ausgebildet ist,
• - eine Transformationseinrichtung, welche zum Erzeugen eines elektrischen Signals abhängig vom dem optischen Übertragungssignal ausgebildet ist,
• - eine Kopplungseinrichtung, welche zum Einkoppeln des elektrischen Signals in eine Quantenbit-Einheit, welche zumindest ein Quantenbit aufweist, und zum Auskoppeln eines elektrischen Kontrollsignals, welches auf dem elektrischen Signal basiert und mit welchem ein Zustand des zumindest einen Quantenbits charakterisiert werden kann, aus der Quantenbit-Einheit ausgebildet ist, und
• - einem elektrischen Ausgang, welcher zum Bereitstellen des elektrischen Kontrollsignals ausgebildet ist.

One aspect of the invention relates to an integrated circuit for a quantum computer, comprising:

• - an optical input, which is designed to receive an optical transmission signal,
• - a transformation device which is designed to generate an electrical signal depending on the optical transmission signal,
• - a coupling device, which is used to couple the electrical signal into a quantum bit unit, which has at least one quantum bit, and to couple out an electrical control signal, which is based on the electrical signal and with which a state of the at least one quantum bit can be characterized, from the Quantum bit unit is formed, and
• - an electrical output, which is designed to provide the electrical control signal.

Thanks to the integrated circuit according to the invention, a quantum computer in particular can be manufactured or provided with reduced installation space and costs. Above all, a quantum computer can be implemented and operated more easily using the integrated circuit.

With the help of the integrated circuit, the preparation, control and measurement of quantum bits or qubits of a quantum computer can be carried out or realized more easily. This can be realized, for example, by coupling in the electrical signal, which is, for example, a signal or radiation in the mm wavelength range. This means, for example, that quantum states of the quantum bit or several quantum bits can be monitored.

With the help of the proposed integrated circuit, for example, highly stable electronics can be provided for generating radiation in the mm-wave range (microwave range). The proposed integrated circuit requires cost-minimized electronics and less installation space, so that this can be used particularly advantageously for quantum computers.

In previous quantum computers, especially in the prior art mentioned, the radiation in the mm-wave range is transmitted through coaxial cables and waveguides in the mm-wave range. These have high attenuation and reduce the quality factor of a quantum bit, for example. In order to transmit this radiation through the coaxial cables, a high cooling capacity is required in the quantum computers used in the prior art. It is precisely here that the integrated circuit according to the invention is advantageously used, since the transmission of the optical transmission signal takes place via an optical input, so an optical transmission takes place here. The conversion of this optical signal into the electrical signal nal, which is in particular in a microwave frequency range, takes place within the integrated circuit. This means that a simple transmission of optical signals can first take place to the integrated circuit and only then can they be converted into an electrical signal or into electromechanical radiation. As a result, the cooling effort of the quantum computer can be minimized or reduced.

For example, the integrated circuit according to the invention can be designed as an electronic-photonic co-integrated circuit or chip. Such an electronic-photonically cointegrated chip can be referred to as a so-called EPIC chip. An electronic-photonically cointegrated semiconductor circuit, in particular the integrated circuit according to the invention, can therefore be used for the preparation, control and measurement of quantum bits in a quantum computer. Using the integrated circuit, microwave radiation can be generated in a frequency range between 1 gigahertz and 300 gigahertz through the optical transmission of the optical transmission signal. For example, a frequency conversion from the terahertz spectral range to the microwave spectral range can be carried out using the electronic-photonically cointegrated semiconductor circuit. Furthermore, the circuit according to the invention can be used to generate, manipulate and convert terahertz radiation or terahertz signals into the microwave range.

What is particularly advantageous in the integrated circuit according to the invention is the cointegration or integration of a photonic-electronic circuit on one and the same semiconductor as the quantum bits of the quantum computer. Thus, for example, quantum gates, such as the HADARMARD gate, can be generated by cointegrated microwave sources on the same chip as the quantum bits.

For example, the integrated circuit can be manufactured by co-integration of electronic photonic elements and the quantum bits. Silicon photon technology can be used for cointegration. This enables the monolithic integration of photonic components, high-frequency electronics and digital electronics together on one chip. A technical information of such a system lies in the signal transmission of gigahertz signals using the optical carrier signal in the terahertz frequency range. A central station, which can also be referred to as a central electronic computing device, generates an optical carrier frequency in the terahertz range, like the optical transmission signal. The transmission signal is modulated on this and transmitted to the integrated circuit, for example, via optical fibers. For this purpose, for example, the frequency can be increased eightfold.

For example, the integrated circuit can be designed as a photonic-electronic semiconductor chip. Furthermore, the integrated circuit can also be referred to as an integrated circuit (English: “Integrated Circuit IC”).

For example, the proposed integrated circuit can achieve the highest degree of miniaturization at the chip level for the quantum computer, so that less cooling power is required. Furthermore, the proposed circuit offers the advantage that there is less attenuation in the microwave wave range and therefore less signal amplification is necessary. Furthermore, a reduction in the required chip area can be achieved, especially compared to conventional electronics. Furthermore, when used in a quantum computer, the integrated circuit offers the advantage that a dephasing time of the quantum bits and a coherence time of the quantum bits can be increased. At the same time, a reduction in the error rate of the quantum bits can be achieved. Furthermore, a cost reduction can be achieved compared to conventional electronics for generating highly stable microwave radiation. For this purpose, the use of standard telecommunications lasers, for example CW lasers, in particular for generating the optical transmission signal, can be used in a particularly advantageous manner.

For example, the integrated circuit can be produced or manufactured on a semiconductor chip in ZMOS, SEN-CMOS, DI-CMOS, hybrid DI-CMOS processors on a photonic-electronic cointegrated chip.

Furthermore, the circuit according to the invention can reduce the hardware required for generating microwave radiation or for generating a signal in the microwave frequency range, so that in particular the size and in particular the complexity of a quantum computer can be reduced. Furthermore, the quality of the quantum bits of the quantum computer can be increased, for example, by the present invention. Furthermore, according to the invention, stabilization of the phase noise of microwave sources, i.e. sources for providing microwave radiation, can be achieved. In particular, an improved quantum computer can be realized using the integrated circuit according to the invention.

If necessary, using the integrated circuit according to the invention, a frequency conversion of a terahertz carrier signal can be carried out in the gigahertz frequency range after optical signal transmission.

For example, there are quantum computers with 50 quantum bits in the prior art. Microwave radiation is required to prepare, control and measure the quantum bits. So far, the generation of microwave radiation has been carried out using signal generators for baseband signals, sideband modulators and demodulators. The transmission takes place using coaxial cable and microwave waveguides. This very complex electronic structure can be minimized or prevented by using the integrated circuit according to the invention in a quantum computer.

Quantum computers can have up to 127 quantum bits for calculation. The hardware required to provide the quantum bits (qubits) can be cooled down to a few millikelvins using a helium gyrostat. The spatial dimensions of this structure are often in the range of 2 by 3 square meters. One reason for the high demand for space and provision of the quantum bits is the preparation, control and measurement of the quantum bits. In order to prepare the quantum bits into the states necessary for the calculation, to control the state and to measure the result, radiation in the microwave wave range is used, for example. The supply and processing of these beams to the actual quantum processor takes up a large part of the volume. In addition, generating the radiation requires a lot of material effort. For example, around 250 signal generators in the gigahertz spectral range of over 60 modulators and demodulators for the sidewall signals are required to prepare, control and measure the state of 50 quantum bits. The signals from the signal sources (e.g. AGGs) to the cryostat of the quantum computer are fed via coaxial cable. Within the cryostat, the signals are transmitted through superconducting coaxial cables. This forwarding, as well as an amplification and increase in the signal-to-noise ratio of the signals within the cryostat, takes up a lot of volume and places extreme demands on the quality of the signal connections. For example, there are seven-quantum-bit transmon processors based on silicon. Here, the microwave radiation at a predetermined frequency is guided into superconducting coplanar waves via superconducting coaxial cables to the individual quantum bits. This can be integrated into silicon. However, the signal generation takes place at room temperature outside the cryostat and is supplied inside the cryostat via superconducting coaxial cables with high power losses. The problems just mentioned regarding a quantum computer can be solved by using at least one integrated circuit according to the invention in a quantum computer. This is done through an optical interface for data transmission regarding the measurement, control and preparation of the quantum bits.

A quantum bit can, for example, be the smallest storage information unit of the quantum computer. A quantum bit is based on the laws of quantum mechanics and behaves differently than conventional bits in a normal computer. In contrast to conventional bits, the quantum bit can assume any number of states at the same time. This means that a quantum computer can have significantly greater computing power. In particular, the quantum bit is a two-state quantum system.

For example, with the electrical control signal provided at the electrical output, the at least one quantum bit or several quantum bits can be prepared into a respective state necessary for a calculation of the quantum computer in order to control the state and measure the result.

With the help of the coupling device, the electrical signal, which is based on the optical transmission signal, can be coupled into the quantum bit unit and in particular into the at least one quantum bit, so that the electrical control signal can be coupled out again depending on this coupling.

In particular, the electrical signal is a signal in the microwave frequency range. In particular, the electrical signal is electromagnetic radiation.

In particular, the proposed integrated circuit can be used or integrated in all quantum computers based on microwave technology. These include, for example, technological designs using ion traps, quantum bits, semiconductor spin quantum bits or superconductivity quantum bits.

In one exemplary embodiment it is provided that the coupling device has a circulator unit, wherein the circulator unit is set up to send the electrical signal to the quantum bit unit and the electrical control signal to the electrical output accordingly in a predetermined direction of circulation. In particular, the circulator unit can prevent backflow or feedback or signal retransmission. According to the predetermined or fixed direction of circulation, for example, the electrical signal can first be forwarded or coupled, in particular unchanged, to the quantum bit unit. Depending on the direction of circulation, the electrical control signal can be output or coupled out from the quantum bit unit and in turn the electrical control signal can be passed on to the electrical output in accordance with the predetermined direction of circulation.

The circulator unit can be, for example, a component or a circuit for separating signal directions. For example, a distinction can be made between passive components and active circuits. In particular, the circulator unit of the coupling device can be a passive component of high and ultra-high frequency technology. In particular, the circulator unit can be referred to as a circulator and, for example, have three connections or ports. For example, the respective signal can be fed into one of the ports and passed on to the next port. On an open port it can be forwarded unchanged. Thus, the direction of circulation or the direction of the circulator unit is from the optical input to the quantum bit unit, from the quantum bit unit to the electrical output and from the electrical output back to the optical input. In particular, the circulator can be used to prevent signaling backflow.

In one exemplary embodiment it is provided that the coupling device has an electrical waveguide, wherein the circulator unit and the quantum bit unit are connected to one another by means of the electrical waveguide, wherein the electrical waveguide is designed to couple the electrical signal into the quantum bit unit and the electrical To transmit control signal from the quantum bit unit to the circulator unit. In other words, the electrical signal recorded by the circulator can be passed on to the electrical waveguide and transmitted via the electrical waveguide to the quantum bit unit or to the at least one quantum bit. In the opposite way, the electrical control signal of the quantum bit unit can be transmitted or transferred via the electrical waveguide to the circulator unit and from there to the electrical output. For example, the electrical waveguide can be designed as a strip line. In particular, the electrical waveguide is a coplanar line or a coplanar waveguide (English: “Coplanar Wave Guide”).

In particular, with the help of the transformation device, an optical signal, in particular the optical transmission signal, can be converted into microwave radiation, i.e. the electrical signal, and passed via the electrical waveguide and the circulator unit to the quantum bit unit or to the at least one quantum bit.

In one exemplary embodiment it is provided that the transformation device has an optical photodiode for generating the electrical signal depending on the optical transmission signal. Furthermore, the transformation device can additionally have an amplifier unit, the amplifier unit being designed to increase a frequency of the electrical signal generated by the optical photodiode as a function of a predetermined carrier frequency. In other words, the transformation device can be a converter unit for converting optical signals into electrical or electromagnetic signals or radiation. In particular, the transformation device can be connected or arranged immediately afterwards to the optical input. Thus, the received optical transmission signal can be converted into the electrical signal after receiving. In particular, the electrical signal is generated or generated based on the optical transmission signal.

The optical input can be, for example, an optical coupling element for coupling the optical transmission signal into the integrated circuit.

The conversion of the optical transmission signal into the electrical signal takes place via the optical photodiode. For example, the optical photodiode is an integral part of the transformation device.

In addition, the transformation device can have a control unit for monitoring the conversion process from an optical transmission signal into the electrical signal.

The optical photodiode can be, for example, a detector. Of Wei Alternatively, the amplifier unit can be part of the transformation device or can be electrically coupled to the transformation device.

The amplifier unit can be, for example, a power amplifier, in particular a multiplier unit. The amplifier unit is designed in particular to multiply and provide the optical transmission signal from the frequency to the necessary carrier frequency. This has the advantage that the optical transmission signal does not have to be provided with the full necessary carrier frequency. For example, it can be provided that a fraction of an eighth is chosen. This allows the optical transmission signal to be modulated with one-eighth of a frequency. Thus, the optical input can provide the optical transmission signal at a significantly lower frequency compared to the frequency for later control of the quantum bit. This allows for a simpler and less complex transfer. For example, the amplifier unit can be connected directly downstream of the optical photodiode.

In one exemplary embodiment it is provided that the integrated circuit has a modulation device which is set up to generate an optical output signal depending on the electrical control signal. Furthermore, the integrated circuit can have an optical output for providing the optical output signal. Furthermore, the modulation device can be set up to modulate the electrical control signal onto the optical transmission signal and thus provide it as an optical output signal at the optical output. For example, the modulation device can additionally have a control unit and an amplifier. With this amplifier, the electrical control signal can be amplified accordingly and prepared for modulation. The control unit can be used to monitor the conversion of the electrical signal into the optical signal.

In other words, the integrated circuit can have at least one optical input, at least one electrical output and at least one optical output.

In particular, the integrated circuit can be constructed in such a way that it has an optical input and an electrical output per quantum bit.

In one exemplary embodiment it is further provided that the integrated circuit has an optical return channel which is arranged between the modulation device and the optical input. The optical return channel is designed to return or transmit the optical output signal to the optical input. Accordingly, a transmission of measurement results, in particular the electrical control signal, can take place here through an optical return channel. For this purpose, the electrical signal can be modulated onto an optical carrier signal by an optical modulator and in particular using electronics provided for this purpose, analogous to the generation of the microwave radiation, i.e. the electrical signal. This optical carrier signal can in turn be the original carrier signal, the optical signal, which is guided through the integrated circuit by a waveguide. Accordingly, the optical output signal, which is based on the electrical control signal, can not only be made available via the optical output of an external unit, such as an analysis device, but can also be fed back or fed back to the optical input. A feedback and thus an improved generation of the electrical signal can therefore be carried out here, since the returned optical output signal can be further taken into account.

In a further exemplary embodiment it is provided that the integrated circuit is designed as a one-chip system. Accordingly, the photonic-electronic co-integrated elements can be integrated in addition to the quantum bit unit and thus to the quantum bits on one and the same chip.

A one-chip system (English: “system-on-a-chip”) is understood to mean the integration of all or a large part of the functions of a programmable electronic system on a chip, i.e. an integrated circuit on a semiconductor substrate called monolithic integration. For example, silicon is used as the substrate material, which is also referred to as system-on-silicon (SOS). A one-chip system can be considered a combination of different elements, such as logic circuits, clocking, independent starting, microtechnical sensors, etc., which together provide a specific functionality, for example a circuit for a quantum computer. Such one-chip systems are used, for example, in embedded systems. While conventional systems initially consisted of a microprocessor or microcontroller PC and many other PCs for special functions that were soldered onto a circuit board, the integration density of the system-on-a-chip means that almost all functions can be combined on a single PC. Digital, analog and Mixed-signal functional units can be integrated. The advantage here is that, above all, cost savings, lower energy consumption or power loss and comprehensive miniaturization can be carried out.

In other words, all components of the integrated circuit are integrated on a single integrated circuit. Consequently, the functionality of the quantum computer can be carried out with just a single integrated circuit or a single chip. In other words, the integrated circuit is fully functional as a stand-alone unit. By using a single chip or integrated circuit, the processing or computing power of the quantum computer is carried out.

In other words, all elements for the optical generation of microwave radiation as well as at least one quantum bit or several quantum bits are located on the integrated circuit.

For example, the quantum computer can have several integrated circuits. For this purpose, a respective integrated circuit can have one or more quantum bits. It is particularly advantageous if the integrated circuit has several quantum bits, so that the quantum computer can use the superposition of several quantum bits for data processing or computing power.

The quantum computer can be used particularly advantageously to process or calculate large amounts of data. For this purpose, for example, the quantum computer can be used to process fleet data from a vehicle fleet. For example, such a quantum computer can be used as a backend or server for a vehicle fleet or another multi-vehicle system.

• - die zentrale elektronische Recheneinrichtung dazu eingerichtet ist, die optischen Übertragungssignale für den integrierten Schaltkreis zu erzeugen und das elektrische Ausgangssignal zu empfangen,
• - die zentral elektronische Recheneinrichtung über zumindest eine Glasfaser mit dem optischen Eingang des integrierten Schaltkreises gekoppelt ist.

A further aspect of the invention relates to a quantum computer with at least one integrated circuit according to the previous aspect or an advantageous development thereof and a central electronic computing device, wherein

• - the central electronic computing device is set up to generate the optical transmission signals for the integrated circuit and to receive the electrical output signal,
• - The central electronic computing device is coupled to the optical input of the integrated circuit via at least one optical fiber.

In particular, the quantum computer just proposed can have the integrated circuits described in the previous aspect. In particular, the quantum computer can have several such integrated circuits.

In particular, the central electronic computing device is a physically separate unit from the integrated circuit. In particular, the central electronic computing device is not part of the integrated circuit. The central electronic computing device can be a different semiconductor chip or integrated circuit compared to the integrated circuit.

For example, the entire signal processing and signal evaluation can be carried out with the help of the central electronic computing device.

In particular, the central electronic computing device can generate an optical carrier frequency, in particular the optical transmission signal, in the terahertz frequency range. The signal to be transmitted and optionally further sidebands can be modulated with 1/n of a microwave frequency and sent to the integrated circuit of the quantum computer or quantum processor.

All data can be processed on the central station, in particular the central electronic computing device.

The central electronic computing device is coupled to the optical input of the integrated circuit via one or more glass fibers. Consequently, the optical transmission signal, which was generated by the central electronic computing device, is coupled into the optical fiber and transmitted to the optical input via optical signal transmission. The carrier signal is therefore transmitted via optical transmission paths. In particular, the glass fiber can be a glass fiber line. It is also conceivable that the central electronic computing device is coupled to the optical output of the integrated circuit via an optical fiber.

In particular, the integrated circuit can transmit the control signal to the central electronic computing device for controlling, measuring, checking and/or preparing the at least one quantum bit.

In an exemplary embodiment of the further aspect, it is provided that the central electronic computing device has a laser device for generating the optical transmission signal.

Furthermore, the laser device is set up to couple the optical transmission signals into the at least one glass fiber, which is coupled to the optical input of the radar sensor device. For example, the laser device can additionally have an optical frequency comb. Furthermore, the laser device for coupling the transmission signals into the at least one optical fiber can have an optical switch or a switching center or a connection node, with which, for example, the optical transmission signal or the optical signal can be transmitted to the integrated circuit.

Thus, using the optical switch, the optical transmission signal can be transmitted to multiple integrated circuits and/or to multiple optical inputs.

In particular, the optical transmission signal can be coupled in depending on electrical control signals from a diagnostic unit and/or a control unit.

In particular, with the help of the laser device, which can in particular be a CW laser (“continuous-wave laser”), the optical transmission signal can be generated or generated as a function of a carrier signal, in particular as a function of a carrier frequency. For this purpose, an electrical control signal can in particular be taken into account.

For example, the central electronic computing device can have at least one fiber output and one fiber input.

Furthermore, the central electronic computing device can have an optical control element for adjusting an optical property of the optical transmission signal.

For example, a phase, a polarization and/or a chirp of the optical signal can be adjusted or changed.

A further aspect of the invention relates to a method for operating an integrated circuit according to one of the previous aspects or an advantageous development thereof.

Thus, a method for increasing a quantum bit dephasing time, increasing the quantum bit coherence time and reducing the quantum bit error rate while simultaneously reducing the necessary hardware for microwave radiation generation can be provided. This makes it possible to stabilize the phase noise of microwave sources. Quantum bit quality can thus be increased.

In particular, in the method according to the invention, the electrical signal is generated depending on the received optical transmission signal. Furthermore, the generated electrical signal can be coupled into the quantum bit unit, whereby the electrical control signal is generated, and depending on the generated electrical control signal, the at least one quantum bit of the quantum bit unit can be checked, prepared and/or controlled.

The control signal generated can then be transmitted to the central electronic computing device and further processed there. The control signal is therefore processed in the central electronic computing device that is separate and physically separate from the integrated circuit.

Embodiments of individual aspects of the invention are advantageous embodiments of other aspects. In particular, the respective exemplary embodiments of individual aspects can be viewed as advantageous exemplary embodiments of all other aspects. This applies in the opposite way as well.

Advantageous embodiments of the integrated circuit are to be viewed as advantageous embodiments of the quantum computer and the method. The integrated circuit and the quantum computer have relevant features that enable the method or an advantageous embodiment thereof to be carried out.

For use cases or application situations that may arise with the method and that are not explicitly described here, it can be provided that an error message and/or a request to enter user feedback and/or a standard setting and/or a predetermined one can be issued according to the method Initial state is set.

The invention also includes developments of the quantum computer according to the invention and the method according to the invention, which have features such as those already in connection with the developments of the quantum computer according to the invention integrated circuit have been described. For this reason, the corresponding developments of the quantum computer according to the invention and the method according to the invention are not described again here.

The invention also includes the combinations of the features of the described embodiments.

• 1 ein beispielhaftes Blockschaltbild eines integrierten Schaltkreises für einen Quantencomputer;
• 2 ein beispielhaftes Blockschaltbild einer zentral elektronisches Recheneinrichtung, welche mittels elektrischer und/oder optischer Übertragungswege mit dem integrierten Schaltkreis aus 1 gekoppelt ist;
• 3 ein beispielhaftes Blockschaltbild eines weiteren Ausführungsbeispiels des integrierten Schaltkreises aus 1; und
• 4 eine schematische Darstellung eines Quantencomputers.

Exemplary embodiments of the invention are described below. This shows:

• 1 an exemplary block diagram of an integrated circuit for a quantum computer;
• 2 an exemplary block diagram of a central electronic computing device, which communicates with the integrated circuit by means of electrical and/or optical transmission paths 1 is coupled;
• 3 an exemplary block diagram of a further embodiment of the integrated circuit 1 ; and
• 4 a schematic representation of a quantum computer.

The exemplary embodiments explained below are preferred exemplary embodiments of the invention. In the exemplary embodiments, the components described each represent individual features of the invention that can be viewed independently of one another, which also develop the invention independently of one another and are therefore to be viewed as part of the invention individually or in a combination other than that shown. Furthermore, the exemplary embodiments described can also be supplemented by further features of the invention that have already been described.

In the figures, functionally identical elements are each provided with the same reference numerals.

In the 1 an example view, in particular a block diagram representation, of an integrated circuit 1, in particular a chip, is shown. This can be part of a quantum computer 2 (see 4 ) be. In particular, the integrated circuit 1 can be integrated in the quantum computer 2 or a quantum processor. The integrated circuit 1 is used in particular for data processing or for the computing power or for the processor performance of the quantum computer 2. Such a quantum computer 2 can, for example, have several integrated circuits 3 (see 4 ) exhibit. The quantum computer 2 can therefore have further integrated circuits 3 in addition to the integrated circuit 1. Depending on the performance requirements or processor performance of the quantum computer 2, the number of integrated circuits 1, 3 can be fixed or defined.

The integrated circuit can in particular have or contain quantum bits (“Qbit”) of the quantum computer 2. The quantum bits serve for the actual processor performance or computing power of the quantum computer 2. For example, in one embodiment, the integrated circuit 1 can have at least one quantum bit unit 4, which in turn has at least one quantum bit 5. However, in another embodiment, such as in 1 shown as an example, the integrated circuit 1 has a further quantum bit unit 6 and a further quantum bit 7. Depending on the application or design or architecture of the quantum computer 2, any number of quantum bits can be integrated on the integrated circuit 1.

Like in the 1 Shown as an example, the integrated circuit 1 has two quantum bits 5, 7. These can, for example, be connected in such a way that data, information or signals are transmitted from these two quantum bits 5, 7 to further quantum bits, which are arranged, for example, on other integrated circuits 3. This depends on the system architecture of the quantum computer 2. For example, a transmission line 8 from the two quantum bits 5, 7 to other quantum bits can be used for this.

For the repair, control and measurement of a respective state of the quantum bits of the quantum computer 2, signals in the gigahertz spectral range, i.e. in the microwave frequency range, are required. As already explained at the beginning, these are generated in the prior art by complex, complex and cost-intensive signal generators, for example, and transmitted via special coaxial cables. In order to remedy this, the integrated circuit 1 can be designed as an electronic-photonically cointegrated circuit. Thus, the integrated circuit 1 can have, in addition to the at least one quantum unit 4 and the at least one quantum element 5, elements or components for generating microwave radiation. The quantum computer 2 can thus be formed from at least one electronic-photonically co-integrated chip, a so-called EPC chip. Silicon photonics technology can be used for this. This is made possible by the monolithic Integra tion of photonic components, high-frequency electronics and digital electronics together on one chip.

For this purpose, an optical transmission signal 9 can be transmitted in the integrated circuit 1. This can be done by a central electronic computing device 10 (see 2 ) to be provided. The quantum computer 2 can therefore have several integrated circuits 1, 3. These can be connected by a single central electronic computing device 10 or a central unit via optical and/or electrical transmission paths. Here, the central electronic computing device 10 and the integrated circuit 1 can be physically separate and separate units. For example, the central electronic computing device 10 can generate an electrical control signal with which a laser device 11 (see 2 ) can be controlled or controlled.

The laser device 11 can be, for example, a CW laser. With the help of the laser device 11, the optical transmission signal 9 in particular can be generated. The optical transmission signal 9 can be referred to, for example, as a carrier signal. In particular, the optical transmission signal 9 can be in the terahertz frequency range. This optical transmission signal 9, which is in the terahertz frequency range, can be optically transmitted from the central electronic computing device 10 to the integrated circuit 1. In this way, frequency multiplication, in particular frequency eightfold, can take place. For this purpose, for example, the central electronic computing device 10 can have at least one optical fiber 12 (see 2 ), via which the optical transmission signal 9 can be transmitted to the integrated circuit 1. For receiving this optical transmission signal 9, the integrated circuit 1 can have at least one optical input 13. In order to be able to convert or transform the optical transmission signal 9 into the desired microwave frequency range, the integrated circuit 1 can have a transformation device 14.

With the help of the transformation device 14, an electrical signal, in particular electromagnetic radiation, can be generated in the microwave frequency range depending on the optical transmission signal 9. The transformation device 14 can have an optical photodiode 16 for converting an optical signal into an electrical signal. This can be arranged immediately after the optical input 13. With the help of the optical photodiode 16, the electrical signal 15 can be generated depending on the optical transmission signal 9. Furthermore, the transformation device 14 can have an amplifier unit 17. With the aid of the amplifier unit 17, which can be designed either in one piece or in several parts, a frequency of the converted electrical signal 15 can be increased. The amplifier unit 17 can therefore be referred to as a frequency multiplier unit. For this purpose, for example, the frequency of the converted signal 15 can be adapted to a carrier frequency. This means that a frequency increase can be carried out here. The conversion of the optical transmission signal into the electrical signal 15 and, for example, the frequency increase can be done by means of a control unit 18, which can be referred to as TIA, for example. The amplifier unit 17 as well as the control unit 18 can be part of the transformation device 14.

In particular, the quantum bit unit 4 can be understood as a higher-level unit or system of the at least one quantum bit 5. In particular, the quantum bit unit 4 can have or accommodate at least one quantum bit 5.

For example, the photodiode 16 can be used to detect the optical transmission signal 9. For this purpose, heterodyne detection can be carried out if necessary. Following the photodiode 16, electronic frequency multiplier units can in turn be provided. In order to be able to couple or transmit the converted electrical signal 15 into the at least one quantum bit 5, the integrated circuit 1 has a coupling device 19. The coupling device 19 can, for example, have a circulator unit 20 or a circulator and an electrical waveguide 21. Thus, after conversion and/or frequency multiplication, the electrical signal 15 can be coupled into the quantum bit unit 4 and thus into the quantum bit 5, for example.

Furthermore, the coupling device 19 is optionally designed to, in addition to coupling into the quantum bit unit 4, also couple out signals from the quantum bit 5 or from the quantum bit unit 4. This decoupling is used to be able to control, measure or prepare the quantum bit 5 and its state. For this purpose, an electrical control signal 22 can be coupled out. For this purpose, the electrical signal 15 can be coupled into the quantum bit unit 4 via the electrical waveguide 21 in accordance with a predetermined direction of circulation using the circulator unit 20. Of Furthermore, the electrical control signal 22, which is based on the electrical signal 15, can be derived or coupled out from the quantum bit unit 4. For this purpose, the electrical control signal 22 can be provided or provided to an electrical output 24 of the integrated circuit 1.

The electrical output 24 can be, for example, an electrical connection or an electrical port in order to make the electrical control signal 22 available to other electronic units in the quantum computer 2 or outside the quantum computer 2. For this purpose, for example, the electrical output 24 can be an electronic measuring unit or electronic control unit or an electronic preparation unit with regard to the at least one quantum bit 5.

Using the electrical waveguide 21, a connection between the circulator unit 20 and the quantum bit unit 4 can be established. The electrical waveguide 21 can be, for example, a loop line such as a coplanar line.

For example, in one embodiment, the integrated circuit 1 can be designed as a one-chip system. Thus, all relevant components for the generation and forwarding of the electrical signal 15 and the elements for forwarding or decoupling the electrical control signal 22 can be integrated on one and the same chip as the quantum bit unit 4 and thus the quantum bit 5.

As already mentioned before, the integrated circuit 1 can have several quantum bit units 6 and further quantum bits 7. The explanations just described regarding signal processing, forwarding, conversion, etc. and the associated components are the same.

In the 2 As already mentioned, a schematic block representation of the central electronic computing device 10 is shown. For example, in addition to the optical fiber 12, the computing device 10 can have further optical fibers, which can be supplied with the transmission signal 9 via an optical distribution unit 39 or a distributor in order in turn to be able to supply the several optical inputs 13 of the integrated circuit 1 with optical signals. The optical distribution unit 39 can be designed, for example, as an “optical switch”. Furthermore, an optical control element 25 can be provided, for example, between the laser device 11 and the optical distribution unit 39. This serves to be able to adapt the optical properties or the properties of the optical transmission signal 9. For example, a polarization, a phase, a chirp of the optical transmission signal 9 can be adjusted or changed. As already mentioned previously, the electrical control signal for controlling the laser device 11 can be made available or transmitted to the laser device 11 via an evaluation unit 26 and a control interface 27.

Furthermore, the computing device 10 can have an electrical input 28, at which, for example, the electrical control signal 22 can be made available or transmitted to the computing device 10. An analog-digital converter 29 can be arranged following this electrical input 28. This is in particular an ADC, which serves as a digital interface for converting the electrical control signal 22 into a digital signal, in particular for the evaluation unit 26. Optionally, the digitized electrical control signal 22 can be processed with a signal processing unit 30. The signal processing unit 30 can, for example, have a low-level signal processing unit (for example FFD).

In the 3 Another possible exemplary embodiment is shown with regard to the integrated circuit 1 from the previous figures. In this case, the integrated circuit 1 can additionally have an optical return channel 31, in particular per quantum bit unit. Accordingly, an optical signal can in turn be fed back or fed to the optical input 13 via the return channel 31 before the electrical signal 15 is converted. For this purpose, the electrical control signal 22 can be converted into an optical output signal 32. For this purpose, for example, a modulation device 33, in particular an optical modulator, is provided. For this purpose, for example, the electrical control signal 22 can be made available to the modulation device 33 via the electrical output 24. For this purpose, preprocessing 34 can be carried out between the electrical output 24 and the optical modulation device 33 in order to prepare the signal accordingly. For this purpose, for example, a baseband of the signal can be processed or prepared. In addition to the feedback of the optical output signal 32, this can be made available or transmitted to the central electronic computing device 10 via an optical output 35 of the integrated circuit 1. For this purpose, the computing device 10 can, for example have an optical input 36 (see 2 ). For this purpose, it is now also conceivable that, in addition to the evaluation of the electrical control signal 22, there is also an optical option. The optical output signal 32 can thus be made available to a detection unit 37. This detection unit 37 can be, for example, an optical detection unit, a homodyne detection unit or a heterodyne detection unit. This means that an optical signal is converted into an electrical signal. The analog-digital converter 29 for converting the electrical signal into a digital signal can in turn be connected to the output of this detection unit 37. Furthermore, it is conceivable that the optical output signal 32 is made available to the laser device 11 via a modulation unit 38, so that this backflow or feedback can be carried out here, for example in order to be able to generate the optical transmission signal 9 more precisely and better.

In a possible exemplary embodiment, it is also conceivable that the central electronic computing device 10 and the integrated circuit 1 are integrated on one and the same chip. For example, signal detection of the electrical control signal 22 or the optical output signal 32 takes place on the central electronic computing device 10. For example, a parametric “JOSEPHSON converter” method or a “HEMT” method can be used for this purpose.

Reference symbol list

1

integrated circuit

2

Quantum computers

3

other integrated circuits

4

Quantum unit

5

quantum bit

6

another quantum bit unit

7

another quantum bit

8th

transmission line

9

optical transmission signal

10

central electronic computing device

11

Laser device

12

glass fiber

13

optical input

14

Transformation facility

15

electrical signal

16

photodiode

17

Amplifier unit

18

Control unit

19

Coupling device

20

Circulator unit

21

electrical waveguide

22

electrical control signal

23

Direction of circulation

24

electrical output

25

optical control element

26

Evaluation unit

27

Control interface

28

electrical input

29

Analogue to digital converter

30

Signal processing unit

31

optical return channel

32

optical output signal

33

Modulation device

34

Preprocessing

35

optical output

36

optical input

37

Detection unit

38

Modulation unit

39

optical distribution unit

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2021/0232962 A1 [0004]
• US 11195117 B2 [0005]
• US 2021/0342729 A1 [0006]

Claims (10)

Integrated circuit (1) for a quantum computer (2), comprising: - an optical input (13), which is designed to receive an optical transmission signal (9), - a transformation device (14), which is designed to generate an electrical signal (15) depending on the optical transmission signal (9), - a coupling device (19), which is used to couple the electrical signal (15) into a quantum bit unit (4), which has at least one quantum bit (5), and to couple out an electrical control signal (22), which is based on the electrical signal ( 15) is based and with which a state of the at least one quantum bit (5) is characterized, from which quantum bit unit (4) is formed, and - an electrical output (24), which is designed to provide the electrical control signal (22). Integrated circuit (1) according to Claim 1 , wherein the coupling device (19) has a circulator unit (20), the circulator unit (20) being set up to send the electrical signal (15) to the quantum bit unit (4) and the electrical control signal (22) to the electrical output ( 24) according to a predetermined circulation direction (23). Integrated circuit (1) according to Claim 2 , wherein the coupling device (19) has an electrical waveguide (21), the circulator unit (20) and the quantum bit unit (4) being connected to one another by means of the electrical waveguide (21), the electrical waveguide (21) being designed for this purpose , to couple the electrical signal (15) into the quantum bit unit (4) and to transmit the electrical control signal (22) from the quantum bit unit (4) to the circulator unit (20). Integrated circuit (1) according to one of the preceding claims, wherein - the transformation device (14) has an optical photodiode (16) for generating the electrical signal (15) depending on the optical transmission signal (9), and - the transformation device (14) additionally has an amplifier unit (17), the amplifier unit (17) being designed to increase a frequency of the electrical signal (15) generated by the optical photodiode (16) as a function of a predetermined carrier frequency. Integrated circuit (1) according to one of the preceding claims, comprising: - a modulation device (33), which is set up to generate an optical output signal (32) depending on the electrical control signal (22), and - an optical output (35) for providing the optical output signal (32). Integrated circuit (1) according to Claim 5 , comprising: - an optical return channel (31), which is arranged between the modulation device (33) and the optical input (13), the optical return channel (31) being designed to send the optical output signal (32) to the optical input (13 ). Integrated circuit (1) according to one of the preceding claims, wherein the integrated circuit (1) is designed as a one-chip system. Quantum computer (2) with at least one integrated circuit (1, 3) according to one of the preceding Claims 1 until 7 and a central electronic computing device (10), wherein - the central electronic computing device (10) is set up to generate the optical transmission signal (9) for the integrated circuit (1) and to receive the electrical control signal (22), - the central Electronic computing device (10) is coupled to the optical input (13) of the integrated circuit (1) via at least one optical fiber (12). Quantum computer (2). Claim 8 , wherein - the central electronic computing device (10) has a laser device (11) for generating the optical transmission signal (9), - the laser device (11) is set up to feed the optical into the at least one glass fiber (12), which is connected to the optical input (13) of the integrated circuit (1), and - the central electronic computing device (10) has an optical control element (25) for adjusting an optical property of the optical transmission signal (9). Method for operating an integrated circuit (1) according to one of the preceding Claims 1 until 7 , wherein - the electrical signal (15) is generated depending on the received optical transmission signal (9), - the generated electrical signal (15) is coupled into the quantum bit unit (4), whereby the electrical control signal (22) is generated, and - depending on the electrical control signal (22) generated, the at least one quantum bit (5) the quantum bit unit (4) can be checked, prepared and / or controlled.

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