US-20260127478-A1 - ENTANGLING GATE (AS AMENDED)

Abstract

A quantum computing method includes providing at least one resonator-coupled quantum emitter configured to function as an entangling gate, receiving a plurality of graph states, at least some of the plurality of graph states representing a relationship between qubits therein, and wherein at least one of the qubits in at least two of the plurality of graph states is a photonic qubit, selecting the at least one photonic qubit from each of the at least two of the plurality of graph sates, interacting the selected qubits with the at least one resonator-coupled quantum emitter, and disentangling the at least one resonator-coupled quantum emitter from the selected qubits.

Inventors

• Gil Semo
• Ziv AQUA
• Oded Melamed
• Dan Charash
• Serge ROSENBLUM
• Barak Dayan

Assignees

• QUANTUM SOURCE LABS LTD.
• YEDA RESEARCH AND DEVELOPMENT CO. LTD.

Dates

Publication Date

20260507

Application Date

20251229

Priority Date

20210427

Claims (20)

1. 1 . A quantum computing method, comprising: providing at least one resonator-coupled quantum emitter configured to function as an entangling gate; receiving a plurality of graph states, at least some of the plurality of graph states representing a relationship between qubits therein, and wherein at least one of the qubits in at least two of the plurality of graph states is a photonic qubit; selecting the at least one photonic qubit from each of the at least two of the plurality of graph sates; interacting the selected qubits with the at least one resonator-coupled quantum emitter; and disentangling the at least one resonator-coupled quantum emitter from the selected qubits, wherein disentangling includes at least one of detecting a state of the at least one resonator-coupled quantum emitter or mapping the state of the at least one resonator-coupled quantum emitter to a state of an additional photonic qubit.
2. 2 . The method of claim 1 , wherein the entangling gate is one of a controlled-Z gate (CZ gate), a controlled NOT gate (CNOT gate), a square root of a SWAP gate, or an imaginary SWAP gate (iSWAP gate).
3. 3 . The method of claim 1 , wherein the selected qubits and the additional photonic qubit have at least one degree of freedom associated with at least two or more states.
4. 4 . The method of claim 1 , wherein the mapping is achieved by applying a SWAP gate on the at least one resonator-coupled quantum emitter and the additional photonic qubit.
5. 5 . The method of claim 1 , wherein the state of the at least one resonator-coupled quantum emitter is initialized to be an equal superposition of two ground states.
6. 6 . The method of claim 1 , wherein the at least one resonator-coupled quantum emitter is coupled to a Fabry-Perot cavity.
7. 7 . The method of claim 1 , wherein the at least one resonator-coupled quantum emitter is coupled to a whispering gallery mode cavity.
8. 8 . The method of claim 1 , wherein the at least one resonator-coupled quantum emitter includes at least one of a stationary qubit capable of interacting with photons, a superconducting qubit, a quantum dot, or an atom.
9. 9 . The method of claim 1 , wherein the at least one resonator-coupled quantum emitter includes a rubidium atom or a cesium atom.
10. 10 . The method of claim 1 , wherein the at least one resonator-coupled quantum emitter includes at least one of Strontium, Erbium, Ytterbium, Calcium, Barium, Beryllium, or Magnesium atom.
11. 11 . A quantum computing system, comprising: at least one resonator-coupled quantum emitter configured to function as an entangling gate; a plurality of switches; and at least one processor configured to control the plurality of switches to: receive a plurality of graph states, at least some of the plurality of graph states representing a relationship between qubits therein, and wherein at least one of the qubits in at least two of the plurality of graph states is a photonic qubit; select the at least one photonic qubit from each of the at least two of the plurality of graph states; interact the selected qubits with the at least one resonator-coupled quantum emitter; and disentangle the at least one resonator-coupled quantum emitter from the selected qubits, wherein disentangling includes at least one of detecting a state of the at least one resonator-coupled quantum emitter or mapping the state of the at least one resonator-coupled quantum emitter to a state of an additional photonic qubit.
12. 12 . The system of claim 11 , wherein the entangling gate is one of a controlled-Z gate (CZ gate), a controlled NOT gate (CNOT gate), a square root of a SWAP gate, or an imaginary SWAP gate (iSWAP gate).
13. 13 . The system of claim 11 , wherein the selected qubits and the additional photonic qubit have at least one degree of freedom associated with at least two or more states.
14. 14 . The system of claim 11 , wherein the mapping is achieved by applying a SWAP gate on the at least one resonator-coupled quantum emitter and the additional photonic qubit.
15. 15 . The system of claim 11 , wherein the state of the at least one resonator-coupled quantum emitter is initialized to be an equal superposition of two ground states.
16. 16 . The system of claim 11 , wherein the at least one resonator-coupled quantum emitter includes at least one of a stationary qubit capable of interacting with photons, a superconducting qubit, a quantum dot, or an atom.
17. 17 . The system of claim 11 , wherein the at least one resonator-coupled quantum emitter is coupled to a Fabry-Perot cavity.
18. 18 . The system of claim 11 , wherein the at least one resonator-coupled quantum emitter is coupled to a whispering gallery mode cavity.
19. 19 . The system of claim 11 , wherein the at least one resonator-coupled quantum emitter includes a rubidium atom or a cesium atom.
20. 20 . A non-transitory computer-readable medium including instructions that, when executed by at least one processor, cause the at least one processor to carry out a quantum computing method, comprising: providing at least one resonator-coupled quantum emitter configured to function as an entangling gate; receiving a plurality of graph states, at least some of the plurality of graph states representing a relationship between qubits therein, and wherein at least one of the qubits in at least two of the plurality of graph states is a photonic qubit; selecting the at least one photonic qubit from each of the at least two of the plurality of graph states; interacting the selected qubits with the at least one resonator-coupled quantum emitter; and disentangling the at least one resonator-coupled quantum emitter from the selected qubits, wherein disentangling includes at least one of detecting a state of the at least one resonator-coupled quantum emitter or mapping the state of the at least one resonator-coupled quantum emitter to a state of an additional photonic qubit.

Description

RELATED APPLICATIONS The application is a continuation of U.S. application Ser. No. 18/299,819, filed Apr. 13, 2023, which is a continuation of PCT International Application No. PCT/IB2022/000564, filed Apr. 27, 2022, which is based upon and claims priority to U.S. Provisional Application No. 63/320,454, filed Mar. 16, 2022, and Israeli Patent Application No. 282705, filed Apr. 27, 2021, the entire contents of all of which are incorporated herein by reference. FIELD The present disclosure relates generally to quantum computation using cavity quantum electrodynamics (Cavity QED), and related apparatuses, systems, computer readable media and methods. Some embodiments involve the generation of photonic graph states. BACKGROUND Building commercially useful quantum computers (QC) can be challenging for many reasons, for example due to scalability issues which arise from increasing complexity, noise and crosstalk as more qubits are added. Also, quantum computation algorithms can exploit entangled states, and some quantum computation architectures may use a source of entangled states (also referred to as a Resource State Generator) for obtaining those entangled states. The present disclosure relates to a mechanism for use in or with such a source of entangled states. Currently, quantum computing remains restricted to the proof-of-concept stage, with a relatively small number of qubits sufficient only to demonstrate that quantum computing is feasible in principle. To make quantum computing practical for handling real-world problems, current devices need to be scaled up to handle large numbers of qubits, over 106, including qubits for error correction. Qubits for quantum computing are often hosted in one of three physical platforms (or regimes): superconductors (superconducting states), atoms (e.g. ionic states), and photons (photonic states). The photonic platform offers a number of significant practical advantages over the other platforms. Photons are relatively easy to generate and do not require cryogenic or ultra-high vacuum environments, and construction of micro-miniaturized, reliable photonic devices and their communication infrastructure is accomplished utilizing readily available fabrication technologies. Thus, the photonic platform is currently a leading candidate for achieving the high-level scaling necessary for practical quantum computing devices. The full potential of the photonic platform, however, is not presently realized, in large part because generating entangled photonic states for use as an entanglement resource in photonic quantum computing is currently highly inefficient. Conventional arrangements rely on nonlinear effects in crystals to generate single photons. In order to produce photonic graph states, these photons are entangled in a probabilistic manner using linear optics elements. For this purpose, generated photons should be indistinguishable, generated according to perfectly timed and identically shaped pulses. Unfortunately, this requirement comes at the expense of the generation efficiency. Furthermore, in order to end up with a photonic graph state of a certain number of qubits, the probabilistic entangling process would require a much larger number of initial single photons, and hence a larger number of elements. These points of inefficiency are cumulative and seriously restrict efforts to scale the photonic platform to meaningful numbers of qubits. It is therefore highly desirable to have apparatuses and methods for generating photonic graph states which reduce or eliminate probabilistic processes and their inherent inefficiencies, and which instead deterministically generate photonic graph states at maximal efficiency, or at an improved efficiency, for use as qubits. This goal is met, or facilitated, by embodiments of the present disclosure. SUMMARY A source of entangled states for use in a quantum computation architecture can use a matter-based or a light-based mechanism. Matter-based quantum computation mechanisms, e.g., those using trapped ions, superconducting qubits, or quantum dots, are sometimes considered more efficient for achieving entangled states than light-based ones. Light-based quantum computation mechanisms, e.g., silicon photonics, are considered to be more scalable and modular. So light-based mechanisms may be useful in addressing the above scalability problem. Using the embodiments consistent with the present disclosure, a source of entangled states for use with quantum computation using a high number of qubits may be possible, for example with a photonic quantum computation. Such architectures may also offer a scalable architecture which can be manufactured in a standard silicon fabrication lab. A cavity quantum electrodynamics (Cavity QED) based mechanism for use in the embodiments consistent with the present disclosure can exploit both light and matter properties, and hence can serve as a source of entangled states in such architectures, leading to a scalab