We propose a framework to analyze linear optical circuits based on an analogy with stabilizer formalism in quantum circuits, which provides efficiently computable formulas related to state discriminations. Hence, we analyze a Bell-state discrimination scheme with linear optics and ancillary single photons. With an increasing number of ancilla photons, the success probability of Bell-state discrimination has a maximum of $\frac{403}{512} \simeq 0.787$ at $28$ ancilla photons. By contrast, the corresponding two-qubit measurement asymptotically approaches a maximally entangling measurement.We propose a framework to analyze linear optical circuits based on an analogy with stabilizer formalism in quantum circuits, which provides efficiently computable formulas related to state discriminations. Hence, we analyze a Bell-state discrimination scheme with linear optics and ancillary single photons. With an increasing number of ancilla photons, the success probability of Bell-state discrimination has a maximum of $\frac{403}{512} \simeq 0.787$ at $28$ ancilla photons. By contrast, the corresponding two-qubit measurement asymptotically approaches a maximally entangling measurement.

arXiv:2301.06551Jan 16, 20230 citations

Efficient High-Dimensional Entangled State Analyzer with Linear Optics

Niv Bharos, Liubov A. Markovich, Johannes Borregaard

The use of higher-dimensional photonic encodings (qudits) instead of two-dimensional encodings (qubits) can improve the loss tolerance and reduce the computational resources of photonic-based quantum information processing. To harness this potential, efficient schemes for entangling operations such as the high-dimensional generalization of a linear optics Bell measurement will be required. We show how an efficient high-dimensional entangled state analyzer can be implemented with a linear optics interferometer and auxiliary photonic states. The degree of entanglement of the auxiliary state is much less than in previous protocols as quantified by an exponentially smaller Schmidt rank. In addition, the auxiliary state only occupies a single spatial mode, allowing it to be generated deterministically from a single quantum emitter coupled to a small qubit register. The reduced complexity of the auxiliary states results in a high robustness to imperfections and we show that auxiliary states with fidelities above 0.9 for qudit dimensions 4 can be generated in the presence of qubit error rates on the order of 10%. This paves the way for experimental demonstrations with current hardware.The use of higher-dimensional photonic encodings (qudits) instead of two-dimensional encodings (qubits) can improve the loss tolerance and reduce the computational resources of photonic-based quantum information processing. To harness this potential, efficient schemes for entangling operations such as the high-dimensional generalization of a linear optics Bell measurement will be required. We show how an efficient high-dimensional entangled state analyzer can be implemented with a linear optics interferometer and auxiliary photonic states. The degree of entanglement of the auxiliary state is much less than in previous protocols as quantified by an exponentially smaller Schmidt rank. In addition, the auxiliary state only occupies a single spatial mode, allowing it to be generated deterministically from a single quantum emitter coupled to a small qubit register. The reduced complexity of the auxiliary states results in a high robustness to imperfections and we show that auxiliary states with fidelities above 0.9 for qudit dimensions 4 can be generated in the presence of qubit error rates on the order of 10%. This paves the way for experimental demonstrations with current hardware.

arXiv:2401.15066QuantumApr 18, 20257 citations

IMPLEMENTING MEASUREMENT OPERATORS IN LINEAR OPTICAL AND SOLID-STATE QUBITS

Yukihiro Ota, Sahel Ashhab, Franco Nori

Apr 1, 20141 citation

Efficient linear optical quantum computation

AG White, TB Bell, NK Langford +4 more

Jun 1, 20020 citations

Efficiency limits for linear optical processing of single photons and single-rail qubits

Dominic William Berry, Alexander I. Lvovsky, Barry C. Sanders

We analyze the problem of increasing the efficiency of single-photon sources or single-rail photonic qubits via linear optical processing and destructive conditional measurements. We allow for the use of coherent states and do not limit to photon-counting measurements. We conjecture that, with the limitation that multiphoton components in the output are not permitted, it is not possible to increase the efficiency. We prove this conjecture for several important special cases, and provide extensive numerical results for the general case.We analyze the problem of increasing the efficiency of single-photon sources or single-rail photonic qubits via linear optical processing and destructive conditional measurements. We allow for the use of coherent states and do not limit to photon-counting measurements. We conjecture that, with the limitation that multiphoton components in the output are not permitted, it is not possible to increase the efficiency. We prove this conjecture for several important special cases, and provide extensive numerical results for the general case.

arXiv:quant-ph/0605043Journal of the Optical Society of America BJan 26, 20075 citations

\frac{403}{512} \simeq 0.787

28

ancilla photons. By contrast, the corresponding two-qubit measurement asymptotically approaches a maximally entangling measurement.