Methods for enhancing privacy in delegated quantum computing, and systems for implementing such methods.

Abstract

The present invention relates to a method for enhancing the privacy of delegated quantum computing, the method comprising a client (A) whose objective is to solve a computational problem based on sensitive data and / or using a sensitive algorithm, and a cloud computing service provider (B) which has superior quantum computing capabilities to the client (A) and is therefore capable of solving the problem and / or executing the client's desired algorithm, the method comprising a sequence including a) an optical emitter (10) controlled by the client (A) emits at least one pulse (11) having a specific quantum state (S1); b) a quantum emitter (20) controlled by the provider (B) receives the pulse (11); and c) the quantum emitter (20) emits a single photon (21) supporting a photon qubit (Q2), thereby defining a relationship between the quantum state (S1) of the pulse (11) and the photon qubit (Q2). The present invention also relates to a system for carrying out this method.

Description

[Technical Field]

[0001] This invention relates to a method for enhancing the privacy of delegated quantum computing. The invention also relates to a system for implementing such a method. This invention is in the field of delegated quantum computing. [Background technology]

[0002] A. Broadbent et al., IEEE (2009), presented the original Universal Blind Quantum Computing (UBQC) protocol, which allows a client to hide the computations it is performing on behalf of the client from the quantum service provider. To execute the protocol, the client must send qubit states to a remote quantum server. To do this, the client manipulates these single-photon and qubit systems and sends them to the server.

[0003] Other protocols that achieve the same goal require the client to own a single-photon detector. Such quantum devices are expensive and require in-house experts to handle precisely, thereby severely limiting access to these protocols.

[0004] UBQC using semiclassical optical communication was proposed by V. Dunjko et al. in Phys. Rev. Lett., 108, 200502 (2012). Here, the client only needs to manipulate attenuated laser pulses to execute the protocol, which is a lower technical requirement. However, the server must perform quantum non-destructive (QND) measurements to count the number of photons in each laser pulse without destroying them, which is practically difficult to achieve. The server then has to isolate single photons from each pulse and convert the semiclassical light into qubits. Finally, the server has to entangle these qubits to perform calculations. This protocol does not specify the implementation of these last two operations. Simultaneously with these implementation problems, the semiclassical light also leaks more information than the qubit state in the original UBQC protocol. Therefore, this leakage must also be suppressed in order to restore a secure protocol. [Overview of the Initiative]

[0005] The objective of this invention is to improve protocols for blind delegated quantum computing.

[0006] The main challenges are (1) converting semiclassical optical pulses into qubits while maintaining their properties, (2) entangle these qubits together, and (3) enhancing security.

[0007] For this purpose, the present invention relates to a method for enhancing the privacy of delegated quantum computing. - A client (A) whose purpose is to solve computational problems based on confidential data and / or using confidential algorithms, - A cloud computing service provider (B) having superior computing capabilities to those of client (A), and therefore capable of solving problems and / or executing algorithms desired by the client, The method is, a) A step in which an optical emitter (10) controlled by a client (A) emits at least one pulse (11) having a specific quantum state (S1), b) A quantum emitter (20) controlled by provider (B) receives a pulse (11), c) A sequence including the step of a quantum emitter (20) emitting a single photon (21) that supports a photon qubit (Q2), thereby defining a relationship between the quantum state (S1) of the pulse (11) and the photon qubit (Q2).

[0008] The invention described in claim 1 provides a novel protocol that enables a client to delegate any quantum computation of its choice to a quantum server owned by a service provider, in a manner that protects the privacy of the client's computations and data.

[0009] Fragments of the client's secret key are encoded in the quantum state of each pulse. The server, with the help of a quantum emitter, recombines the pulses into the encrypted qubit state.

[0010] Subsequently, the server can use encrypted qubits to perform the computation of interest to the client via the UBQC protocol, which is driven by classical instructions sent by the client that depend on the computation and secret key.

[0011] With respect to non-classical communication, the blind delegated quantum computing protocol as defined in this way requires the client to send attenuated laser pulses (i.e., semiclassical light) to the server instead of qubit states like in the original UBQC protocol. A quantum emitter with a suitable energy level structure acts as a "pulse-photon qubit converter."

[0012] This protocol is cryptographically secure regardless of the context of execution (configurable security). The security is unconditional, meaning it is maintained without any other assumptions, based solely on the laws of quantum physics, particularly with respect to the adversary's computing power (compared to, for example, RSA encryption, where security relies on the fact that factoring large numbers is difficult for an adversary attempting to break the encryption).

[0013] According to further embodiments of the invention that are advantageous and can be used to define dependent claims, such methods may incorporate one or more of the following features: - The photon (21) is entangled with the quantum emitter (20). -The sequence is repeated such that the quantum emitter (20) emits a series of single photons (21), each supporting a photon qubit (Q2), and a relationship is defined between the quantum state (S1) of the pulse (11) that produces a particular photon (21) from the series of photons and the photon qubit (Q2) supported by this particular photon (21). -Each of the series of photons (21) is entangled with the quantum emitter (20) and the previously emitted photons (21). -The sequence is repeated such that a quantum emitter (20) generates a plurality of photons (24, 25), including a principal photon (24) and an auxiliary photon (25), which are entangled in a structure (26) having at least two dimensions, each photon (24, 25) supporting a photon qubit (Q2), and a relationship is defined between the quantum state (S1) of the pulse (11) that generates a particular photon (24, 25) of the structure (26) and the photon qubit (Q2) supported by this particular photon (24, 25). - The structure is 2D. - The structure is a 3D structure. -Structure (26) is in the Greenberger-Horn-Zeilinger (GHZ) state. -The sequence is repeated such that the quantum emitter (20) emits a series of structures (26). -Each structure (26) in the series of structures is entangled with the quantum emitter (20) and the previously emitted structure (26). -In a further collapse operation, the structure or each structure (26) collapses into a desired single qubit (27). - Provider (B) performs this collapse operation by measuring the auxiliary photon qubit (25) of structure (26). - The measurement for each auxiliary photon qubit is performed on the Hadamard basis (i.e., the X basis of the Bloch sphere). - The optical emitter (10) includes an attenuated laser (14) coupled to a polarization controller (15). - The quantum state (S1) of pulse (11) includes the polarization angle (θ). Each photon (24, 25) in the Greenberger-Horn-Zeilinger (GHZ) state has a different random polarization angle (θ j It is generated by ). The global polarization angle (θ) of each GHz state is equal to the sum of the polarization angles (θj) used during its generation process. - The quantum emitter (20) is a quantum dot. - The quantum emitter (20) is an atom. - The quantum emitter (20) is an ion. The present invention also relates to a system for carrying out the method described above. The system is: - An optical emitter (10) controlled by a client (A) and configured to emit at least one pulse (11) having a specific quantum state (S1), - A quantum emitter (20) controlled by a provider (B), configured to receive a pulse (11) and emit a single photon (21) that supports a photon qubit (Q2), wherein a relationship is defined between the state (S1) of the pulse (11) and the photon qubit (Q2).

[0014] The abstract cryptographic framework used to prove the configurable security of the protocol of the present invention was introduced by U. Maurer and R. Renner, Innovations in Computer Science (2011), and has been applied to UBQC in V. Dunjko et al., ASIACRYPT (2014).

[0015] The deterministic generation of photon entanglement states using quantum emitters was proposed by C. Schon et al., Phys. Rev. Lett., 95, 110503 (2005), and has been adapted by N. Lindner and T. Rudolph, Phys. Rev. Lett., 103, 113602 (2009) to the types of entanglement states required for UBQC. Techniques for generating the entanglement states required for the protocol of the present invention using non-interacting quantum emitters have been proposed by P. Hilaire et al., arxiv 2205.09750 (2022). Experimental demonstrations of this entanglement state generation using quantum emitters have been reported by P. Thomas et al., Nature 608, 677 (2022), D. Cogan et al., Nat. Photon. (2023) and N. Coste et al., arxiv, 2207,09881 (2022).

Brief Description of the Drawings

[0016] The present invention will be described, by way of example and without limiting the object of the present invention, in correspondence with the accompanying drawings. The accompanying drawings are as follows. [Figure 1] It is a schematic diagram of communication between a client (A) and a provider (B). [Figure 2] It is a schematic diagram of a system for implementing the method according to the present invention, including an optical emitter and a quantum emitter. [Figure 3] It is a schematic diagram of one possible atomic level structure of a quantum emitter for photon entanglement. [Figure 4] It is a schematic diagram of the entanglement of a photon with a quantum emitter and previously emitted photons. [Figure 5] This is a schematic diagram of the GHz state and its decay into a highly protected photon qubit via the measurement of the auxiliary photon qubit. [Figure 6] This is a schematic diagram of a series of entangled GHz states. [Figure 7] This is a schematic diagram of an optical emitter that emits a series of pulses. [Figure 8] This is a schematic diagram of the generation of a rotating GHz state by a quantum emitter. [Figure 9] This is a schematic diagram illustrating the separation between the GHz state and the quantum emitter. [Figure 10] This is a schematic diagram of the generation of a series of entangled GHZ states separated from a quantum emitter. [Figure 11] This is a schematic diagram of the auxiliary qubit measurement. [Figure 12] This is a schematic diagram of the formation of a secure qubit. [Modes for carrying out the invention]

[0017] For this purpose, the present invention relates to a method for enhancing the privacy of delegated quantum computing, and includes a client (A) and a cloud computing service provider (B).

[0018] Client (A) wishes to solve a computational problem based on confidential data and / or using a confidential algorithm. Service provider (B) has superior computing capabilities to client (A) and can be used to solve this problem and / or to execute the client's desired algorithm.

[0019] Figure 1 shows the communication between a client (A) and a provider (B).

[0020] Client (A) wants to perform a calculation, for example, solve problem f based on confidential data x. Client (A) has limited computing power and cannot solve the problem themselves. Client (A) wants to delegate the calculation to Provider (B), which has a server, i.e., a supercomputer. Provider (B) returns the calculation result / solution y to Client (A).

[0021] However, client (A) does not want provider (B) to obtain information about its problem. Provider (B) should not learn f, x, or y.

[0022] In the case of quantum algorithms, if a client (A) can prepare simple qubit states and send them to a provider (B) that has access to a more powerful quantum computer, the UBQC protocol allows the client (A) to instruct the provider (B) to blindly execute the desired quantum algorithm.

[0023] The "blind" property means that neither the provider (B) nor any eavesdropper knows anything about the quantum algorithm, the client's (A) inputs, or outputs. The UBQC protocol guarantees this based solely on physical laws (unconditional security).

[0024] However, preparing, processing, and transmitting qubit states is difficult and costly.

[0025] It is possible to reduce the technical requirements on the client (A) side. They only need to prepare attenuated laser pulses and send them to the provider (B). This requires far fewer technical requirements for both generation and communication compared to sending qubits using the original UBQC protocol.

[0026] Figure 2 shows a system (1) configured to carry out the method according to the present invention.

[0027] The client (A) has an optical emitter (10) configured to emit at least one pulse (11) having a specific quantum state (S1). Preferably, the optical emitter (10) includes a laser optical emitter, which is a technique currently used to interact with a quantum emitter (20). More preferably, the optical emitter (10) comprises an attenuated laser (14) coupled to a polarization controller (15). The quantum state (S1) of the pulse (11) depends on the polarization angle (θ).

[0028] Provider (B) has a quantum emitter (20) configured to receive a pulse (11) and emit a single photon (21) that supports a photon qubit (Q2). The quantum emitter (20) may be a quantum dot, an atom, or an ion. The quantum emitter (20) is a single-photon (21) spontaneous emitter that supports a photon qubit (Q2). The quantum emitter (20) may be optically manipulated with a decayed laser pulse (11).

[0029] A relationship is defined between the state (S1) of the pulse (11) and the photon qubit (Q2). The state (S1) of the laser pulse (11) is transferred to the emitted photon qubit (Q2) at the same polarization angle (θ) around the Z-axis. Other relationships between the laser pulse state and the generated state can also be used, such as rotation around a different polarization axis, or a larger set of states where unitary operations that transform one state into another state in the set form a multiplicative group.

[0030] In Figure 2, -α = average number of photons in the laser pulse (11), proportional to the laser power. ·|α〉 L ,|α〉 R =Quantum states (S1) of left-polarized and right-polarized laser pulses (11), respectively. |L〉, |R〉 = Quantum states of photon qubits (Q2) representing left- or right-polarized photons. • |↑〉, |↓〉 = Quantum state of quantum emitter (20) • θ = the polarization angle of the laser (and subsequent qubits), which acts as the client's (A) secret key to encrypt their calculations (this value must not be leaked to the server operated by the service provider (B)).

[0031] This delicious, a) The optical emitter (10) emits at least one pulse (11) having a specific quantum state (S1), and b) the quantum emitter (20) receives the pulse (11). c) A sequence including the step of a quantum emitter (20) emitting a single photon (21) that supports a photon qubit (Q2), thereby defining a relationship between the quantum state (S1) of the pulse (11) and the photon qubit (Q2).

[0032] In this sequence, the consecutive steps a) and c) each have a timescale on the order of one-tenth of a nanosecond. The timescale of step b) depends on the distance between the client (A) and the service provider (B). The sum of these timescales is limited by the coherence time of the quantum emitter (20), i.e., the period during which the quantum emitter (20) can be controlled as a quantum system with known quantum states.

[0033] By controlling the polarization of the laser (10), client (A) can control the polarization of the photon qubit (Q2) during emission. This constitutes the secret key of client (A) in the UBQC protocol.

[0034] Figure 3 shows one possible atomic-level structure of a quantum emitter (20) for generating photons (21) that are entangled in the quantum emitter (20). The polarization |L〉 or |R〉 of the emitted photons (21) depends on the state of the quantum emitter (20) |↑〉 or |↓〉.

[0035] Figure 4 shows the entanglement between the newly emitted photon (21) and the quantum emitter (20), and the entanglement with the previously emitted photon (21).

[0036] This operation is performed automatically during step c) of the sequence described above. In each step c), the newly emitted photon (21) is entangled with the quantum emitter (20).

[0037] This sequence is repeated in which, in successive step a), multiple successive attenuated laser pulses (11) are transmitted with different polarization angles (θ), and in successive step c), a quantum emitter (20) emits a series of single photons (21), each supporting a photon qubit (Q2), thereby defining a relationship between the quantum state (S1) of the pulse (11) that produces a particular photon (21) from the series of photons and the photon qubit (Q2) supported by this particular photon (21). This relationship is related to the polarization angle (θ).

[0038] Each photon (21) in the sequence of photons (21) is entangled with the quantum emitter (20) and the previously emitted photons (21). The first emitted photon (21) is entangled with the quantum emitter (20) insofar as there is a chain of photons (21) linking it to the quantum emitter (20) in the structure—graph representation—of the quantum state (S1).

[0039] At this stage, another challenge is to enhance the security of the protocol. This is because a higher laser power a increases the probability of emitting photons (21), but also increases the amount of information leaked to the server operated by the provider (B). In other words, the server can learn more information from a laser pulse (11) than from a single qubit (Q2). Therefore, leakage needs to be reduced.

[0040] To do this, we combine multiple emitted photons (21) in such a way that the server must obtain information about all of their polarizations in order to completely break the security of the protocol. Thus, security can be increased to any high level. We prove this using an abstract cryptographic framework, which means that the protocol of the present invention is configurably secure. This security-enhancing gadget is highly compatible with the entangled state generation scheme of the present invention, which is described below, and can be run simultaneously in the same configuration. This significantly reduces the technical requirements for implementation.

[0041] Figure 5 shows the use of structure (26) to reduce protocol leakage and enhance security.

[0042] This sequence is repeated in successive step c) such that the quantum emitter (20) generates a plurality of photons (24, 25) entangled in a structure (26) having at least two dimensions.

[0043] The structure (26) can be 2D or 3D. The basic protocol requires only a 2D structure. However, a 3D structure can potentially add error correction capability to the protocol (particularly to protect against photon loss).

[0044] Preferably, structure (26) may be a Greenberger-Horn-Zeilinger (GHZ) state, as shown in the example in Figure 5. A GHZ state is a quantum state whose structure can be described by a graph centered on a single vertex and branching to all other vertices. Each vertex corresponds to a qubit initialized to a specific state, and each edge corresponds to an entanglement operation.

[0045] The structure (26) includes a main photon (24) and an auxiliary photon (25), which are also referred to as an inner photon (24) and an outer photon (25). Each photon (24, 25) supports a photonic qubit (Q2), and a relationship is defined between the quantum state (S1) of a pulse (11) generating a specific photon (24, 25) of the structure (26) and the photonic qubit (Q2) supported by this specific photon (24, 25).

[0046] This relationship is related to the polarization angle (θ j ). In successive step a), a plurality of successive attenuation laser pulses (11) are transmitted at different values of the polarization angle (θ j ), and in successive step c), each of a plurality of photonic qubits (21) of the structure (26) has a polarization angle (θ j ).

[0047] The qubit (Q2) is entangled in the rotated GHZ state |L…L〉 + e iθ |R…R〉, θ = Σ θj . Then, the service provider (B) collapses the qubit (Q2) into the desired single qubit (27) state |L〉 + e iθ |R〉 by measuring the outer qubit in the GHZ state.

[0048] Figure 6 shows a series of entangled GHZ states.

[0049] The sequence is repeated such that the quantum emitter (20) emits a series of structures (26). Each structure (26) of the series of structures is entangled with the quantum emitter (20) and the previously emitted structure (26).

[0050] Figures 7 to 12 show a series of sequences.

[0051] Figure 7 represents a series of step a) where the client (A) sequentially transmits laser pulses (11) at different random values of the polarization angle (θ j ).

[0052] Figure 8 illustrates a series of steps c) in which the provider (B) uses these pulses (11) to emit photons (24, 25) using the quantum emitter (20). The overall state of the structure (26) thus produced is that its polarization is at all angles θ = Σ θj This is the GHZ state rotated by the sum of the values.

[0053] Figure 9 illustrates the step in which the provider (B) applies an Adamard operation to the quantum emitter (20) to separate the generated GHz state from the emitter (20). Figure 10 illustrates the repetition of the above steps with a polarization angle θj of a different random value each time, as long as the quantum emitter (20) is not decoherent (i.e., does not lose its quantum properties).

[0054] Figure 11 shows the step in which the provider (B) measures the outer photon qubit (25) of the structure (26).

[0055] Figure 12 shows the final step in which each structure (26) collapses into a desired single qubit (27). More precisely, a measurement performed on the outer qubit (25) of structure (26) transmits the polarization of the GHZ state to the main inner qubit (24), which then has the desired state with the same polarization. The final state in Figure 12 has the same structure as the structure in Figure 4, but the probability of not losing information from each qubit is enhanced in the process.

[0056] Therefore, the present invention solves these three problems.

[0057] 1. Provider (B) needs to convert the attenuated laser pulse (11) into a photon qubit (Q2) while maintaining the characteristics of the state (Q1) of the laser pulse (11). This is actually a very difficult task using conventional techniques.

[0058] 2. The provider (B) needs to entangle the photon qubits (Q2) with each other, that is, to make them interact quantum mechanically. This is an inherently probabilistic and demanding operation if it is performed independently of the qubit generation process (e.g., nonlinear interactions with atoms or inherently probabilistic gates in optical quantum circuits).

[0059] 3. Since the laser pulse (11) leaks more information about the client (A)'s calculations than the original UBQC qubits, the protocol must enhance the privacy of the client (A) and restore the initial security of the UBQC. This technology must be compatible with the solutions to problems 1 and 2.

[0060] By solving these three problems, the method according to the present invention makes UBQC using semiclassical light practical.

[0061] The present invention eliminates the need for QND measurements and entanglement gates by using a quantum emitter with a suitable energy level structure that functions as a "pulse-photon qubit converter" and can deterministically entangle photons as needed to execute any delegated quantum algorithm.

[0062] The protocol of the present invention simplifies its implementation so that it can be used in any context in which UBQC is relevant. This capability becomes particularly important when quantum computers become large enough to perform some interesting tasks better than classical computers. A client (A) with sensitive data or innovative algorithms may not want to transmit it to a quantum cloud service provider (B) in an unprotected state. On the other hand, the cost of acquiring and operating a large-scale quantum computer on the client's (A) premises would be prohibitive for client (A).

[0063] Blind delegation protocols, which are technically easy to implement on both the client (A) and provider (B) sides, mitigate these problems, and therefore, client (A) is more willing to perform high-impact but sensitive computations on provider (B)'s quantum server without requiring mutual trust or complex legal agreements. This impacts all applications of quantum computing that fall into this category and their related industries, from drug design and medical data analysis to defense.

[0064] It is important to note that performing BQC using classical computers is impossible with the same level of security. All protocols rely on assumptions of certain computational difficulty. For example, the RSA encryption scheme is secure as long as the adversary cannot efficiently factorize large numbers. On the other hand, the protocols of this invention are secure regardless of the adversary's computing power. Access to more powerful computers does not diminish the security of the protocols of this invention. This is called unconditional or statistical security.

[0065] Furthermore, the protocol according to the present invention is configurable, meaning it has been proven to remain secure regardless of the context in which it is executed. It can be used as a building block in any protocol of our choice, either in parallel with or consecutively with any other protocol.

[0066] Finally, the security of the protocol of the present invention increases exponentially with the number of photons in the GHz state. More precisely, if the probability of leaking information about a single photon is p, then for N photons, the probability of leaking the state after the state collapse is p N This is the case. This decreases very quickly with N and can be made arbitrarily small.

[0067] Other embodiments not shown can also be implemented within the scope of the invention as defined by the claims. Furthermore, the technical features of different embodiments can be combined with each other, either whole or in part. Thus, the Method and System 1 can be adapted to the specific requirements of an application.

Claims

1. A method for enhancing the privacy of delegated quantum computing, - A client (A) whose purpose is to solve computational problems based on confidential data and / or using confidential algorithms, - A cloud computing service provider (B) having computing capabilities superior to those of the client (A), and therefore capable of solving the problem and / or executing the client's desired algorithm, The aforementioned method, a) The optical emitter (10) controlled by the client (A) emits at least one pulse (11) having a specific quantum state (S1), b) A quantum emitter (20) controlled by the provider (B) receives the pulse (11), c) A method comprising a sequence including the step that the quantum emitter (20) emits a single photon (21) that supports a photon qubit (Q2), thereby defining a relationship between the quantum state (S1) of the pulse (11) and the photon qubit (Q2).

2. The method according to claim 1, wherein the photon (21) is entangled in the quantum emitter (20).

3. The method according to claim 1 or 2, wherein the sequence is repeated such that the quantum emitter (20) emits a series of single photons (21), each supporting a photon qubit (Q2), and a relationship is defined between the quantum state (S1) of the pulse (11) that generates a particular photon (21) from the series of photons and the photon qubit (Q2) supported by this particular photon (21).

4. The method according to claims 2 and 3, wherein each photon (21) of the series of photons is entangled with the quantum emitter 20) and previously emitted photons (21).

5. The method according to any one of claims 1 to 4, wherein the sequence is repeated such that the quantum emitter (20) generates a plurality of photons (24, 25) including a principal photon (24) and an auxiliary photon (25) entangled in a structure (26) having at least two dimensions, each photon (24, 25) supporting a photon qubit (Q2), and a relationship is defined between the quantum state (S1) of the pulse (11) that generates a particular photon (24, 25) of the structure (26) and the photon qubit (Q2) supported by this particular photon (24, 25).

6. The method according to claim 5, wherein the structure (26) is in a Greenberger-Horn-Zeilinger (GHZ) state.

7. The method according to claim 5 or 6, wherein the sequence is repeated such that the quantum emitter (20) emits a series of structures (26).

8. The method according to claim 7, wherein each of the series of structures (26) is entangled with the quantum emitter (20) and the previously emitted structure (26).

9. The method according to any one of claims 5 to 8, wherein in a further collapse operation, the structure or each structure (26) collapses into a desired single qubit (27).

10. The method according to claim 9, wherein the provider (B) performs the collapse operation by measuring the auxiliary photon qubit (25) of the structure (26).

11. The method according to any one of claims 1 to 10, wherein the optical emitter (10) comprises an attenuated laser (14) coupled to a polarization controller (15).

12. The method according to any one of claims 1 to 11, wherein the quantum state (S1) of the pulse (11) includes a polarization angle (θj).

13. Each photon (24, 25) in the Greenberger-Horn-Zeilinger (GHZ) state has a different random polarization angle (θ ｊ The global polarization angle (θ) of each Greenberger-Horn-Zeilinger (GHZ) state is generated by the same process as the polarization angle (θ) used during the generation process. ｊ The method according to claims 6 and 12, wherein the sum of the two is equal to the sum of the two.

14. The method according to any one of claims 1 to 12, wherein the quantum emitter is a quantum dot, an atom, or an ion.

15. A system for carrying out the method described in any one of claims 1 to 14, - An optical emitter (10) controlled by the client (A) and configured to emit at least one pulse (11) having a specific quantum state (S1), - A quantum emitter (20) controlled by the provider (B), configured to receive the pulse (11) and emit a single photon (21) that supports a photon qubit (Q2), wherein a relationship is defined between the state (S1) of the pulse (11) and the photon qubit (Q2), A system equipped with these features.

Images