A programmable high-dimensional quantum computing chip structure based on integrated optics

Abstract

The present invention provides a programmable high-dimensional quantum computing chip based on integrated optics, which realizes optical unitary transformation by regulating the multi-photon path entangled state prepared by the entangled multi-photon source and the universal linear optical network, so as to realize programmable high-dimensional quantum bit calculation by performing different linear combinations of unitary transformation. The chip includes: a configurable entangled multi-photon source, which is used to generate multi-photons, obtain linear term coefficients, and output multiple photons according to wavelengths; an initial state configuration linear optical network (O), which is used to prepare quantum initial states for photons output by the configurable entangled multi-photon source; a unitary operator configuration linear optical network (U), which is used to realize optical unitary transformation, and beam combination to realize linear combination of unitary transformation; a projection measurement linear optical network (T), which is used to perform projection measurement on the light quantum state after beam combination. The technical solution of the present invention can realize a programmable and controllable universal high-dimensional quantum computing chip.

Description

Technical Field

[0001] The present invention relates to the field of quantum computing technology, and in particular to a programmable high-dimensional quantum computing chip based on integrated optics. Background Art

[0002] Quantum computing is a new computing model that follows the laws of quantum mechanics and performs calculations by controlling quantum information units, namely quantum bits. Quantum computing uses the superposition, interference and entanglement characteristics of quantum to perform calculations. It has natural parallelism and large information storage capabilities, and thus has huge potential that cannot be matched by classical computing. It has great application potential in many fields such as large number prime factorization, database search, chemical molecular simulation, etc.

[0003] Linear optical systems are one of the main physical approaches to quantum computing. Their main advantages include: photons have a very long coherence time and are not easily decohered by external interference; photons are easy to control with high precision; and the multiple degrees of freedom of photons can be used to encode high-dimensional quantum.

[0004] Many quantum computing applications can be experimentally realized in linear optical systems, most of which are discrete component optical systems. When using discrete component optical systems to implement programmable quantum computing, it is necessary to modulate the discrete optical components, which is difficult to experiment with and has high requirements for experimental technology. In addition, free-space linear optical systems require a large number of discrete optical components, the entire system is huge, and each discrete component is easily affected by factors such as ambient temperature and vibration, which limits the stability and scalability of the system.

[0005] Integrated optical quantum chips use integrated optical technology to integrate discrete linear optical components into a single semiconductor integrated chip in the form of thin films. Compared with discrete component optical systems, not only is the volume significantly reduced, but the entire system has better stability and scalability due to its high integration. Integrated optical quantum chips can achieve the miniaturization and integration of discrete component optical systems on large optical platforms, and are considered to be the most effective way to realize large-scale optical quantum computing systems.

[0006] At present, most linear optical quantum systems use parametric down-conversion or four-wave mixing effects to probabilistically generate single photon pairs. In theory, a deterministic single photon source can be achieved, but there are still considerable technical difficulties to overcome, so photon resources are relatively expensive overall. On the other hand, single photons have multiple degrees of freedom, and high-dimensional encoding and manipulation of single photons can significantly reduce the demand for photon resources in optical quantum computing. Based on the preparation and manipulation characteristics of high-dimensional quantum states of photons, combined with the advantages of integrated optical quantum chip technology, it can provide a new way to improve the computing power of linear optical quantum computing systems. Summary of the invention

[0007] The present invention provides a programmable high-dimensional quantum computing chip based on integrated optics, which realizes the preparation, manipulation and projection measurement of high-dimensional light quantum states on-chip, thereby realizing a general high-dimensional quantum computing chip in which high-dimensional quantum state input, high-dimensional quantum gate operation and high-dimensional quantum state projection measurement can all be programmably controlled.

[0008] The present invention provides a programmable high-dimensional quantum computing chip based on integrated optics, comprising: a linear coefficient configuration network, N entangled multi-photon sources and a wavelength division multiplexer, for generating multiple photons, wherein the number of entangled photons generated by each entangled multi-photon source is denoted as P, and photons of different wavelengths are respectively output according to the wavelength through the wavelength division multiplexer, and the pump light entering the interference configuration network is configured according to the output path by adjusting the first phase shifter and the second phase shifter in the linear coefficient configuration network, so as to obtain a set of linear configuration coefficients, which are denoted as α1, α2...α N ; Initial configuration linear optical network O, connected to the configurable entangled multi-photon source, forming corresponding O1, O2...O according to the wavelength of the output photon of the wavelength division multiplexer P , used to prepare the initial state of the photons output by the configurable entangled multi-photon source; the unitary operator configures the linear optical network U, which is correspondingly connected to the initial state configuration linear optical network O to form the corresponding U1 (i) ,U2 (i) ...U P (i) (i=1,2,...N), used to perform unitary transformation. After beam combination, the linear combination of unitary operators is realized to obtain the final quantum state result: The projection measurement linear optical network T is connected to the unitary operator configuration linear optical network U to form corresponding T1, T2...T P Used to perform projection measurement on the light quantum state after beam combining.

[0009] According to a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network all belong to universal linear optical networks.

[0010] According to a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention, the configurable entangled multi-photon source, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network all implement path encoding through the first phase shifter and the second phase shifter.

[0011] According to a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention, the linear coefficient configuration network includes log2N-level Mach-Zehnder interferometers, which are arranged in the form of a "binary tree", that is, each output port of the upper-level Mach-Zehnder interferometer is connected to an input port of a Mach-Zehnder interferometer of the next level, and the output port of the last-level Mach-Zehnder interferometer is connected to an input port of a Mach-Zehnder interferometer of the next level. An output port is connected to a second phase shifter and an entangled multi-photon source, wherein the Mach-Zehnder interferometer includes a first phase shifter and two multi-mode interferometers connected to the first phase shifter.

[0012] In the present invention, the programmable high-dimensional quantum computing chip based on integrated optics can be implemented in the form of: Quantum computing, where is the quantum operation to be realized, expressed as a linear combination of multiple linear optical unitary transformations U, where α i is the linear term coefficient, and the initial state is calculated as It is a multi-photon high-dimensional quantum state.

[0013] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, the configurable entangled multi-photon source generates photons of P wavelengths, and the photons of the P wavelengths are respectively routed to P groups of initial state configuration linear optical networks, where P is a natural number and P≥2.

[0014] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, the initial configuration linear optical network may include a multi-level chain structure.

[0015] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, the unitary operator configured linear optical network may be an optical network structure with a triangular distribution.

[0016] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, the projection measurement linear optical network may include an inverse tree structure.

[0017] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, the first phase shifter and the second phase shifter adjust each light path through an external classical control signal to achieve path coding.

[0018] According to a programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention, each group of the P groups of initial state configuration linear optical networks has N initial state configuration linear optical networks; correspondingly, the unitary operator configuration linear optical networks are divided into P groups, each group has N, and the number of the projection measurement linear optical networks is P; wherein each group of unitary operator configuration linear optical networks is correspondingly connected to a group of initial state configuration linear optical networks and one projection measurement linear optical network.

[0019] The programmable high-dimensional quantum computing chip structure based on integrated optics provided by the present invention generates multiple photons and encodes the path of the entangled multi-photon source, and performs initial state preparation, unitary transformation, linear combination, beam combining and projection measurement on photons routed according to wavelengths through a universal linear optical network, thereby realizing the generation, manipulation and measurement of quantum information carriers on a single integrated optical chip, thereby making it possible to realize an integrated, miniaturized, scalable and programmable quantum computing device.

[0020] The programmable high-dimensional quantum computing chip based on integrated optics provided by the embodiment of the present invention realizes the integration of optical chips for quantum computing. Compared with the discrete component optical system, not only the volume is significantly reduced, but also the whole system has better stability and better scalability due to the high integration. The large-scale programmable high-dimensional quantum computing chip technology based on integrated optics can support the scalable implementation of the linear combination scheme based on unitary operators, construct a fully programmable high-dimensional quantum bit computing chip, and realize multi-qubit quantum information processing based on photons.

[0021] The embodiment of the present invention realizes high-dimensional quantum bit computing by adopting a linear combination method of unitary operators based on path coding, and realizes optical unitary transformation by regulating the multi-photon path entangled state prepared by a configurable entangled multi-photon source and the unitary operator configuration linear optical network, thereby realizing high-dimensional multi-bit quantum computing by combining on-chip high-dimensional multi-photon path entanglement and a linear combination method based on path coding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is one of the schematic diagrams of the structure of a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention;

[0024] Figure 2This is the second schematic diagram of the structure of a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention;

[0025] Figure 3 It is a schematic diagram of the quantum computing process flow in a programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention;

[0026] Figure 4 It is a schematic diagram of the optical network structure for initial state preparation provided by the present invention;

[0027] Figure 5 It is a schematic diagram of the triangularly distributed optical network structure provided by the present invention;

[0028] Figure 6 It is a schematic diagram of the optical network structure for photon beam combining provided by the present invention;

[0029] Figure 7 It is a schematic diagram of the optical network structure for projection measurement provided by the present invention;

[0030] Figure 8 It is a schematic diagram of the structure of an integrated optical chip for realizing four-dimensional quantum bit computing using two-photon entangled states provided by the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, an embodiment of the present invention provides a programmable high-dimensional quantum computing chip based on integrated optics, including: a configurable entangled multi-photon source 102, including a linear coefficient configuration network, N entangled multi-photon sources and a wavelength division multiplexer, for generating multiple photons, the number of entangled photons generated by each entangled multi-photon source is recorded as P, photons of different wavelengths are output according to the wavelength through the wavelength division multiplexer, and the pump light entering the interference configuration network is configured according to the output path by adjusting the first phase shifter and the second phase shifter in the linear coefficient configuration network to obtain a set of linear configuration coefficients, which are recorded as α1, α2…α N .

[0034] Initial configuration linear optical network 104 is connected to the configurable entangled multi-photon source, and corresponding O1, O2...O are formed according to the wavelength of the output photon of the wavelength division multiplexer. P , used to prepare the initial state of the photons output by the configurable entangled multi-photon source.

[0035] The unitary operator configuration linear optical network 106 is connected to the initial configuration linear optical network O to form a corresponding U1 (i) , U2 (i) …U P (i) (i=1,2,...N) is used to perform unitary transformation. After beam combination, the linear combination of unitary operators is realized to obtain the final quantum state result:

[0036] Specifically, the linear combination refers to linearly combining unitary transformations implemented by different optical networks.

[0037] The projection measurement linear optical network 108 is connected to the unitary operator configuration linear optical network U to form corresponding T1, T2...T P , used for projection measurement of the light quantum state after beam combining.

[0038] Specifically, projection measurement is to spectrally decompose a Hermitian operator representing an observable quantity on a system state space into multiple measurement operators. This measurement operator is actually the projection of the Hermitian operator onto the eigensubspace generated by the corresponding eigenvalue.

[0039] In an embodiment of the present invention, by encoding the configurable entangled multi-photon source module, the linear term coefficients of the entangled multi-photon source path can be configured, and by configuring the linear optical network by the initial state and the unitary operator, the unitary operator of the initial state and the linear combination can be configured, so as to realize the organic combination and matching of the multi-photon source that can prepare the multi-photon path entangled state and the universal linear optical network that can realize the unitary transformation. The programmable high-dimensional quantum computing chip based on integrated optics of the embodiment of the present invention has the characteristics of programmability and scalability. By regulating the multi-photon path entangled state prepared by the entangled multi-photon source and the optical unitary transformation realized by the universal linear optical network, the programmable high-dimensional quantum computing chip based on integrated optics can prepare multi-photon high-dimensional entangled quantum states and realize programmable high-dimensional quantum bit calculation.

[0040] Quantum chip technology based on integrated optics has made great progress. This technology uses semiconductor micro-nano processing technology to integrate discrete optical components into a single chip. Compared with discrete optical components, it has the advantages of small size, high stability, and strong scalability. It is an effective way to realize large-scale optical quantum computing systems.

[0041] The field of integrated optical quantum chips has developed rapidly in recent years, and the important components required for integrated optical quantum computing have been experimentally verified, including on-chip single photon sources and entangled photon sources, on-chip high-precision quantum state manipulation, on-chip linear optical networks, etc. Based on these basic units or modules, through the careful design of the optical chip structure, the generation, manipulation and measurement of quantum information carriers - photons - can be achieved on a single chip, making it possible to realize integrated, miniaturized, scalable and programmable quantum computing devices.

[0042] The large-scale integrated photonic quantum chip technology can support the scalable implementation of the linear combination scheme based on unitary operators, construct a fully programmable high-dimensional quantum bit computing chip, and realize multi-qubit quantum information processing based on photons. At the same time, the manufacturing process of programmable high-dimensional quantum computing chips based on integrated optics such as silicon-based optical waveguides can be compatible with CMOS. The programmable high-dimensional quantum computing chip based on integrated optics in the embodiment of the present invention can be further integrated with the traditional CMOS computing chip for the future design of photonic quantum information processing chips with optoelectronic fusion and hybrid architecture.

[0043] In an embodiment of the present invention, an integrated light source may be provided on the programmable high-dimensional quantum computing chip based on integrated optics to generate photons and output them to the linear coefficient configuration network. A single-photon detector may be integrated on the programmable high-dimensional quantum computing chip based on integrated optics to detect photons output by the linear optical network. The single-photon detector may be an avalanche photodiode or a superconducting nanowire detector.

[0044] Among them, initial state configuration linear optical network, unitary operator configuration linear optical network and projection measurement linear optical network all belong to universal linear optical networks.

[0045] The configurable entangled multi-photon source, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network all achieve path encoding through the first phase shifter and the second phase shifter.

[0046] like Figure 2 As shown, a Mach-Zehnder interferometer includes a phase shifter 211 and two multi-mode interferometers 212 connected to the phase shifter 211 .

[0047] like Figure 2As shown, the first-stage Mach-Zehnder interferometer of the log2N-stage Mach-Zehnder interferometer receives an input light beam 221 from the outside of the configurable entangled multi-photon source 102, and the log2N-stage Mach-Zehnder interferometer forms N light paths according to the input light beam 221, and outputs the N light paths to N entangled multi-photon sources 215. Here, each entangled multi-photon source is connected to a second phase shifter 214. All phase shifters of the configurable entangled photon source module are used to adjust the light paths output by the linear coefficient configuration network to configure the coefficients of the linear terms. Specifically, the first phase shifter and the second phase shifter adjust the light paths through an external classical control signal to obtain the linear term coefficients. As shown Figure 2 As shown, the configurable entangled multi-photon source 102 also includes a wavelength division multiplexer 216.

[0048] like Figure 2 As shown, the general linear optical network includes:

[0049] Initial configuration linear optical network 201 is connected to the configurable entangled multi-photon source, and corresponding O1, O2...O are formed according to the wavelength of the output photon of the wavelength division multiplexer. P , used to prepare the initial state of the photons output by the configurable entangled multi-photon source.

[0050] The unitary operator configures the linear optical network 202 (including the beam combiner 231), which is connected to the initial configuration linear optical network O to form the corresponding U1 (i) ,U2 (i) ...U P (i) (i=1,2,...N), used to perform unitary transformation. After beam combination, the linear combination of unitary operators is realized to obtain the final quantum state result:

[0051] The projection measurement linear optical network 203 is connected to the unitary operator configuration linear optical network U to form corresponding T1, T2...T P , used for projection measurement of the light quantum state after beam combining.

[0052] like Figure 2 As shown, the programmable high-dimensional quantum computing chip structure based on integrated optics in the embodiment of the present invention includes N entangled multi-photon sources and The N entangled multiphoton sources can be labeled as S1, S2, ..., S N , where N is a natural number and N ≥ 2. The Mach-Zehnder interferometers in the first-stage Mach-Zehnder interferometer network are arranged in the form of a binary tree, that is, each output port of the previous-stage Mach-Zehnder interferometer is connected to an input port of a Mach-Zehnder interferometer of the next-stage, and the N output ports of the last-stage Mach-Zehnder interferometer are connected to a second phase shifter and an entangled multi-photon source.

[0053] By setting the first phase shifter and the second phase shifter in the configurable entangled multi-photon source to configure the various paths of light output by the linear coefficient configuration network accordingly, different linear term coefficients can be obtained as needed. Each entangled multi-photon source generates P photons with different wavelengths.

[0054] After passing through the wavelength division multiplexer, the photons are routed to the entrances of the P groups of initial state configuration linear optical networks, and the function of the initial state configuration linear optical network is to prepare the initial state.

[0055] Since each multiphoton source generates P photons with different wavelengths, photons with the same wavelength are routed to the same set of initial configuration linear optical networks. Figure 2 As shown, in the embodiment of the present invention, the number of initially configured linear optical networks is set to P groups, and the P groups of initially configured linear optical networks can be marked as: O1, O2, ..., O P . Wherein, P is a natural number and P≥2. Each group of initial configuration linear optical networks has N numbers.

[0056] Through O1, O2, ..., O P It is possible to prepare a t-dimensional quantum state encoding P paths, where the initial state O1, O2, ..., O P It can be any t-dimensional linear optical operation. For each O in the chip M , can perform the same operation, where M is a natural number and 1≤M≤P.

[0057] The number of unitary operator configured linear optical networks is P*N, which can be divided into P groups, each group including N unitary operator configured linear optical networks. Among them, the first group of unitary operator configured linear optical networks U1 is connected to the first group of initial state configured linear optical networks O1, the second group of unitary operator configured linear optical networks U2 is connected to the second group of initial state configured linear optical networks O2, and the Pth group of unitary operator configured linear optical networks U P With the Pth group of initial configuration linear optical network O P Corresponding connection.

[0058] Specifically, the unitary operator configuration linear optical network can be marked as U1 (1) , U1 (2) …U1 (N) , U2 (1), U2 (2) …U2 (N ), …, U P (1) , U P (2) …U P (N) .

[0059] The number of projection measurement linear optical networks is P, and each projection measurement linear optical network corresponds to a set of O and U. The P projection measurement linear optical networks can be marked as: T1, T2, ...T M ,…T P , each T M Each has t ports.

[0060] The initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network are all universal linear optical networks that can realize t-dimensional unitary transformation.

[0061] In the related art, in mathematics, a unitary transformation is a transformation that preserves the inner product, and the inner product of two vectors before the unitary transformation is equal to the inner product after the transformation. A unitary transformation is a transformation made using a unitary operator. There are transformations of basis vectors and transformations of operators. It can be considered that a unitary transformation is an isomorphism between two Hilbert spaces.

[0062] Specifically, if we want to realize a certain unitary matrix V T ——Here V T It can be expressed as V T =α j U j , (j=0, 1, 2…n-1), where U j is a gate acting on the d-dimensional target (T) subspace, α j is a complex coefficient, satisfying When the controlled U j When gates are available, we can implement V in a probabilistic way T α j The initial state encoded as k-qubit control (C) Where n = 2 k , j marks the computational basis, and when all control qubits are finally measured to be 0 in the computational basis, the circuit is successful. By moving the partial state of the target qubit to the extended Hilbert space, the control qubit can more simply act on the single qubit unitary. In an embodiment of the present invention, a technique based on the extended computational Hilbert space can be used to implement a linear combination circuit.

[0063] Any quantum unitary operation can in principle be decomposed into a linear sum of elementary operations. For example, using Cartan's KAK decomposition, any two-qubit unitary operation can be rewritten to be converted into a linear combination of four linear terms, each of which is the tensor product of two single-qubit gates. In addition, the Cartan decomposition method allows n-qubit unitary operations to be reconstructed as a linear combination of the tensor products of n single-qubit gates. In order to achieve linear combinations of quantum operations, it is necessary to add coherent control for arbitrary unknown quantum operations, a technique based on gates that extend the logical Hilbert space used for computation.

[0064] Each entangled multi-photon source generates P photons with different wavelengths. According to the needs, the paths of the N entangled multi-photon sources are first encoded by adjusting the phase shifters in the configurable entangled multi-photon source to obtain the coefficients of the linear terms α1, α2, ...α N ,get After passing through the wavelength division multiplexer, the photons enter different initial configuration linear optical networks according to their wavelengths, and are finally output from different projection measurement linear optical networks. Combined with post-selection technology, coincidence measurement of P photons of different wavelengths is performed at the projection measurement linear optical network. Corresponding multi-photon multi-path entangled states are generated at the entrances of each optical network in the initial configuration linear optical network. In the initial configuration linear optical network, the Mth group of photons with the same wavelength |M>1|M>2…|M> N Each photon is routed to the initial configuration linear optical network O M Generate the initial state, then route to the unitary operator to configure the linear optical network U M (1) , U M (2) , ..., U M (N) Unitary transformation and linear combination are performed to combine the optical paths. After beam combining, the linear combination of unitary operators is realized to obtain the final quantum state result: Finally enter the projection measurement optical network T M , and perform projection measurement on the light quantum state. Among them, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network are all multiple t-dimensional configurable linear optical networks. According to the different entangled states of multi-dimensional entangled photons, the initial state configuration linear optical network is recorded as O1, O2, ... O M , …O P , where M is a natural number and 1≤M≤P, each group O M There are N of them.

[0065] As shown in 3, in the embodiment of the present invention, the module 311 composed of the configurable entangled multi-photon source and the unitary operator configuration linear optical network is used to perform step 321: perform coefficient configuration and unitary operator linear combination; the initial state configuration linear optical network 312 is used to perform step 322: perform arbitrary initial state preparation; the projection measurement linear optical network 313 is used to perform step 323: perform projection measurement. Here, step 321, step 322 and step 323 can be collectively referred to as step 331: implementation of unitary operator linear combination based on photon path state encoding.

[0066] In an embodiment of the present invention, the initial configuration linear optical network may be as follows: Figure 4 The multi-stage chain structure shown in the figure, the unitary operator configuration linear optical network can contain a Figure 5 The t-dimensional simplified triangular optical network structure shown in the figure is Figure 6 This is a schematic diagram of the optical network structure used for photon beam combining. The projection measurement linear optical network can be as follows: Figure 7 The reverse tree structure is shown.

[0067] For the initial configuration linear optical network, the initial quantum state can generally be set to |0>, that is, input from the first path mode.

[0068] The quantum computing operations performed on the programmable high-dimensional quantum computing chip based on integrated optics are realized by a path-encoded unitary operator linear combination scheme, in which the linear coefficients are provided by a configurable entangled multi-photon source, the unitary operator linear combination is provided by a unitary operator configured linear optical network, the unitary operator configured linear optical network includes N*P linear optical networks that can realize the required t-dimensional unitary transformation, and the Mth group of photons with the same wavelength |M>1|M>2…|M> N Each photon is routed to the initial configuration linear optical network O M Generate the initial state. Then route to the unitary operator to configure the linear optical network U M (1) , U M (2) ,…,U M (N) Complete unitary transformation and linear combination. Finally, route to the projection measurement linear optical network to complete the projection measurement.

[0069] The programmable high-dimensional quantum computing chip based on integrated optics in the embodiment of the present invention uses integrated optics technology to integrate discrete linear optical elements in the form of thin films onto a single semiconductor integrated chip. Compared with discrete component optical systems, not only is the volume significantly reduced, but the entire system also has better stability and better scalability due to its high degree of integration.

[0070] The important components required for programmable high-dimensional quantum computing chips based on integrated optics have been experimentally realized, such as on-chip single photon sources and entangled photon sources, on-chip wavelength division multiplexers, on-chip universal linear optical network implementations, etc. Based on these integrated chip components, using on-chip integrated photon sources to generate entangled photons, using on-chip integrated Mach-Zehnder interferometers and linear optical networks composed of phase controllers to control the behavior of photons, and then using on-chip integrated single photon detectors to detect photons, it is possible to design large-scale programmable high-dimensional quantum computing chips based on integrated optics to realize complex quantum information processing applications.

[0071] In an embodiment of the present invention, an on-chip path entangled multi-photon source and a universal linear optical network are used together to establish an integrated optical chip structure through a programmable high-dimensional quantum computing chip approach based on integrated optics. Specifically, in an embodiment of the present invention, different multi-photon multi-path entangled states are generated through an on-chip path entangled multi-photon source, and different optical unitary transformations are configured through an on-chip universal linear optical network to achieve different computing tasks according to needs; quantum information processing results can be obtained by performing output measurements, thereby achieving universal quantum information computing.

[0072] In an embodiment of the present invention, the first phase shifter and the second phase shifter in the entangled multi-photon source module adjust each light path through an external classical control signal, encode the paths of N entangled multi-photon sources, and obtain linear term coefficients.

[0073] In an embodiment of the present invention, each group of initial state configuration linear optical networks in P groups of initial state configuration linear optical networks contains N networks; correspondingly, the unitary operator configuration linear optical network is divided into P groups, each group of N networks, and the number of projection measurement linear optical networks is P; wherein, each group of unitary operator configuration linear optical networks is correspondingly connected to a group of initial state configuration linear optical networks and one projection measurement linear optical network.

[0074] Among them, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network are all universal linear optical networks that can be configured in multiple t dimensions.

[0075] Through the programmable high-dimensional quantum computing chip approach based on integrated optics, a multi-photon source that can prepare multi-photon path entangled states is organically combined with a linear optical network that can realize unitary transformations. By regulating the multi-photon source to prepare multi-photon path entangled states, and configuring different optical unitary transformations through the on-chip universal linear optical network, this programmable high-dimensional quantum computing chip based on integrated optics can prepare multi-particle high-dimensional entangled light quantum states and realize programmable high-dimensional quantum bit calculations by linear combinations of unitary operators.

[0076] The above describes a technical solution for realizing t-dimensional quantum bit calculation using N-dimensional entangled light quantum states of P particles.

[0077] like Figure 8 As shown, a schematic diagram of the structure of a programmable high-dimensional quantum computing chip based on integrated optics for realizing four-dimensional quantum bit computing.

[0078] In the configurable entangled multi-photon source 801, the initial state of the two-photon source is configured by adjusting the phase shifter in the configurable entangled multi-photon source 801 to obtain the coefficients α1 and α2 of the linear term. Each entangled multi-photon source generates a frequency-entangled photon pair, and a wavelength division multiplexer is used to separate the signal photons and idler photons generated by the entangled photon source through four-wave mixing. The configurable entangled multi-photon source 801 generates photons of two wavelengths and routes them to different networks of the initial state configuration linear optical network 802 according to the wavelength.

[0079] The initial state configuration linear optical network 802 prepares the entangled photons obtained by the entangled multi-photon source into any initial state as required, and then routes them to the unitary operator configuration linear optical network 803. The unitary operator configuration linear optical network 803 includes four linear optical networks, namely, U1 (1) 、U1 (2) 、U2 (1) and U2 (2) , which are all 4-dimensional linear optical network structures, can realize the linear combination scheme of unitary operators based on path coding.

[0080] The unitary operator configures the linear optical network 803 to route the linearly combined photons to the projection measurement linear optical network 804 for projection measurement.

[0081] In the embodiment of the present invention, the paths of the two entangled multi-photon sources are first encoded by adjusting the phase shifter in the configurable entangled multi-photon source 801 to obtain the coefficients α1 and α2 of the linear term, and then: After passing through the wavelength division multiplexer, the photons enter different linear optical networks according to their wavelengths, and are finally output from different projection measurement optical networks. Combined with post-selection technology, coincidence measurement of two photons of different wavelengths is performed at the projection measurement optical network. Corresponding multi-photon multi-path entangled states are generated at the entrances of each optical network in the initial configuration linear optical network. In the initial configuration linear optical network, each photon in the Mth group of photons with the same wavelength |M>1|M>2 is routed to the initial configuration linear optical network O M Generate the initial state, then route to the unitary operator to configure the linear optical network U M (1) , U M (2)Form a linear combination, and finally combine the light path to enter the projection measurement linear optical network T M , and perform analysis and measurement. Here, M = 1 or 2. The initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network are all 4-dimensional configurable linear optical networks.

[0082] In the present invention, the programmable high-dimensional quantum computing chip based on integrated optics can be implemented in the form of: Quantum computing, where is the quantum operation to be realized, expressed as a linear combination of multiple linear optical unitary transformations U, where α i is the linear term coefficient, and the initial state is calculated as The result of quantum computing is multi-photon high-dimensional quantum state.

[0083] like Figure 8 The entire programmable high-dimensional quantum computing chip structure based on integrated optics can be controlled by 97 phase shifters. These phase shifters adjust each light channel through external classical control signals, and by applying different external classical control signals to each phase shifter, the programmability of the optical quantum computing chip can be achieved. The final result =

[0084] In another embodiment of the present invention, the configurable entangled multi-photon source includes three entangled multi-photon sources, each of which generates three photons with different wavelengths. As required, the paths of the three entangled multi-photon sources are first encoded by adjusting the phase shifters in the configurable entangled multi-photon source to obtain the coefficients α1, α2, and α3 of the linear terms, and then: After passing through the wavelength division multiplexer, the photons enter different initial configuration linear optical networks according to their wavelengths, and are finally output from different projection measurement linear optical networks. Combined with post-selection technology, coincidence measurement of three photons of different wavelengths is performed at the projection measurement optical network. Corresponding multi-photon multi-path entangled states are generated at the entrances of each optical network in the initial configuration linear optical network. In the initial configuration linear optical network, each photon in the Mth group of photons with the same wavelength |M>1|M>2|M>3 is routed to the initial configuration linear optical network O M Generate the initial state, then route to the unitary operator to configure the linear optical network U M (1) , U M (2) , U M (3) Form a linear combination, combine the light paths and finally enter the projection measurement optical network T M , and perform analytical measurement. Here, M is 1, 2 or 3. The final obtained

[0085] In another embodiment of the present invention, the configurable entangled multi-photon source includes two entangled multi-photon sources, each of which generates three photons with different wavelengths. As required, the paths of the two entangled multi-photon sources are first encoded by adjusting the phase shifter in the configurable entangled multi-photon source to obtain the coefficients α1 and α2 of the linear term, and then: After passing through the wavelength division multiplexer, the photons enter different initial configuration linear optical networks according to their wavelengths, and are finally output from different projection measurement linear optical networks. Combined with post-selection technology, coincidence measurement of three photons of different wavelengths is performed at the projection measurement optical network. Corresponding multi-photon multi-path entangled states are generated at the entrances of each optical network in the initial configuration linear optical network. In the initial configuration linear optical network, each photon in the Mth group of photons with the same wavelength |M>1|M>2 is routed to the initial configuration linear optical network O M Generate the initial state, then route to the unitary operator to configure the linear optical network U M (1) , U M (2) Form a linear combination, combine the light paths and finally enter the projection measurement optical network T M , and perform analytical measurement. Here, M is 1, 2 or 3. The final result =

[0086] The embodiment of the present invention realizes high-dimensional quantum bit computing by adopting a linear combination method of unitary operators based on path coding, and realizes optical unitary transformation by regulating the multi-photon path entangled state prepared by the entangled multi-photon source and the unitary operator configuration linear optical network, thereby combining on-chip high-dimensional multi-photon path entanglement and the linear combination method based on path coding to realize high-dimensional multi-bit quantum computing.

[0087] Among them, the coefficients of the optical unitary operation terms of the linear combination are configured by the phase shifter in the configurable entangled multi-photon source, the preparation of each initial state is realized by configuring the linear optical network through the initial state, and each term and linear combination of the unitary transformation is realized by configuring the linear optical network through the unitary operator, and finally the calculation result is obtained by projection measurement through the projection measurement linear optical network. Based on this, the programmable high-dimensional quantum computing chip based on integrated optics can complete multi-particle high-dimensional entangled optical quantum states to realize high-dimensional quantum bit calculation.

[0088] The programmable high-dimensional quantum computing chip based on integrated optics provided by the present invention generates multiple photons and encodes the path of the entangled multi-photon source, and performs initial state preparation, unitary transformation, linear combination and projection measurement on the photons routed according to the wavelength through a linear optical network, thereby realizing the functions of generating, controlling and measuring quantum information carriers on a single integrated optical chip, thereby making it possible to realize an integrated, miniaturized, scalable and programmable quantum computing device.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A programmable high-dimensional quantum computing chip based on integrated optics, characterized in that: include: A configurable entangled multi-photon source includes a linear coefficient configuration network, N entangled multi-photon sources and a wavelength division multiplexer, which is used to generate multiple photons. The number of entangled photons generated by each entangled multi-photon source is recorded as P. Photons of different wavelengths are output according to their wavelengths through the wavelength division multiplexer. By adjusting the first phase shifter and the second phase shifter in the linear coefficient configuration network, the pump light entering the interference configuration network is configured according to the output path, and a set of linear configuration coefficients is obtained, which are recorded as α1, α2...α N ; Initial configuration linear optical network O is connected to the configurable entangled multi-photon source, and corresponding O1, O2...O are formed according to the wavelength of the output photon of the wavelength division multiplexer. P , used to prepare an initial state for the photons output by the configurable entangled multi-photon source; The unitary operator configures the linear optical network U, which is connected to the initial configuration linear optical network O to form the corresponding U1 (i) ,U2 (i) ...U P (i) (i=1,2,...N), used to perform unitary transformation. After beam combination, the linear combination of unitary operators is realized to obtain the final quantum state result: The projection measurement linear optical network T is connected to the unitary operator configuration linear optical network U to form corresponding T1, T2...T P , used to perform projection measurement on the light quantum state after beam combining.

2. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network all belong to universal linear optical networks.

3. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The configurable entangled multi-photon source, the initial state configuration linear optical network, the unitary operator configuration linear optical network and the projection measurement linear optical network all achieve path encoding through the first phase shifter and the second phase shifter.

4. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The linear coefficient configuration network includes log2 N-stage Mach-Zehnder interferometers arranged in the form of a "binary tree", that is, each output port of the previous-stage Mach-Zehnder interferometer is connected to an input port of a Mach-Zehnder interferometer of the next stage, and the output port of the last-stage Mach-Zehnder interferometer is connected to an input port of a Mach-Zehnder interferometer of the next stage. An output port is connected to a second phase shifter and an entangled multi-photon source, wherein the Mach-Zehnder interferometer includes a first phase shifter and two multi-mode interferometers connected to the first phase shifter.

5. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The configurable entangled multi-photon source generates photons of P wavelengths, and the photons of the P wavelengths are respectively routed to P groups of initial state configuration linear optical networks, where P is a natural number and P≥2.

6. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The initial configuration linear optical network may include a multi-level chain structure.

7. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The unitary operator-configured linear optical network may be an optical network structure with a triangular distribution.

8. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 1, characterized in that: The projection measurement linear optical network may comprise an inverse tree structure.

9. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 3, characterized in that: The first phase shifter and the second phase shifter adjust each light path through an external classical control signal to achieve path coding.

10. The programmable high-dimensional quantum computing chip based on integrated optics according to claim 5, characterized in that: Each group of the P groups of initial state configuration linear optical networks has N initial state configuration linear optical networks; correspondingly, the unitary operator configuration linear optical networks are divided into P groups, each with N numbers, and the number of the projection measurement linear optical networks is P; wherein each group of unitary operator configuration linear optical networks is correspondingly connected to a group of initial state configuration linear optical networks and one projection measurement linear optical network.

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