Quantum tomography of photon states encoded in polarization and picosecond time bins

Pilnyak, Y.; Zilber, Pini; Cohen, Lior; Eisenberg, Henryk

doi:10.1103/physreva.100.043826

Cited by 11 publications

(7 citation statements)

References 31 publications

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“…The birefringent material changes the phase and polarization of entangled photons in the sample arm, and the density matrix of the entangled states reflects these changes, as evident in Figure 2a-d. Concurrence and the entanglement levels are computed using Equations ( 8) and (11), for DQST and IQST methods, respectively, from the density matrices. DQST measurements of concurrence and entanglement without tape are 82.99% ± 0.3101 and 76.2% ± 0.8355, while IQST estimation of concurrence is 91.04% ± 0.0102 and 87.27% ± 0.0284 for entanglement.…”

Section: Resultsmentioning

confidence: 99%

“…Reconstruction of concurrence and entanglement images are computed for each pixel and follow from Equations ( 8) and (11), respectively. In this work, two-level quantum entangled photons are generated in a type-II crystal via spontaneous parametric downconversion (SPDC) [20,21].…”

Section: Entanglement Computationmentioning

confidence: 99%

“…The technique extracts information about the quantum state of a system. Inverse techniques offer significant improvement over the direct quantum tomography approach [4][5][6][7][8][9][10][11][12][13][14]. Yet, very little work was done to experimentally demonstrate image enhancement and the superiority of the inverse techniques.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we compare images of birefringent samples obtained from the reconstructed density matrix of entangled states between two techniques, direct quantum state tomography (DQST) and inverse numerical optimization quantum state tomography (IQST). Both are linearly related to a set of measured coincidence rates [4][5][6][7][8][9][10][11][12][13][14]. A number of inverse algorithms were proposed with faster convergence time [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Polarization Sensitive Imaging with Qubits

Sukharenko

Dorsinville

2022

Applied Sciences

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We compare reconstructed quantum state images of a birefringent sample using direct quantum state tomography and inverse numerical optimization technique. Qubits are used to characterize birefringence in a flat transparent plastic sample by means of polarization sensitive measurement using density matrices of two-level quantum entangled photons. Pairs of entangled photons are generated in a type-II nonlinear crystal. About half of the generated photons interact with a birefringent sample, and coincidence counts are recorded. Coincidence rates of entangled photons are measured for a set of sixteen polarization states. Tomographic and inverse numerical techniques are used to reconstruct the density matrix, the degree of entanglement, and concurrence for each pixel of the investigated sample. An inverse numerical optimization technique is used to obtain a density matrix from measured coincidence counts with the maximum probability. Presented results highlight the experimental noise reduction, greater density matrix estimation, and overall image enhancement. The outcome of the entanglement distillation through projective measurements is a superposition of Bell states with different amplitudes. These changes are used to characterize the birefringence of a 3M tape. Well-defined concurrence and entanglement images of the birefringence are presented. Our results show that inverse numerical techniques improve overall image quality and detail resolution. The technique described in this work has many potential applications.

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Section: Resultsmentioning

confidence: 99%

Section: Entanglement Computationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polarization Sensitive Imaging with Qubits

Sukharenko

Dorsinville

2022

Applied Sciences

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“…Moreover, fiber plays a central role in the quantum telecommunications infrastructure. Fiber interferometric systems are particularly critical for time-based data manipulation (e.g., executing projection measurements on time-bin-encoded states using imbalanced interferometers [23][24][25][26] ) with reduced coupling losses versus, e.g., fiber-to-chip coupling. However, stability and full phase control are not easily achievable in fiber interferometric systems, currently limiting their potential use.…”

Section: Introductionmentioning

confidence: 99%

Arbitrary Phase Access for Stable Fiber Interferometers

Roztocki

MacLellan

Islam

et al. 2021

Laser & Photonics Reviews

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Well-controlled yet practical systems that give access to interference effects are critical for established and new functionalities in ultrafast signal processing, quantum photonics, optical coherence characterization, etc. Optical fiber systems constitute a central platform for such technologies. However, harnessing optical interference in a versatile and stable manner remains technologically costly and challenging. Here, degrees of freedom native to optical fibers, i.e., polarization and frequency, are used to demonstrate an easily deployable technique for the retrieval and stabilization of the relative phase in fiber interferometric systems. The scheme gives access (without intricate device isolation) to <1.3 × 10 −3 rad error signal Allan deviation across 1 ms to 1.2 h integration times for all tested phases, ranging from 0 to 2 . More importantly, the phase-independence of this stability is shown across the full 2 range, granting access to arbitrary phase settings, central for, e.g., performing quantum projection measurements and coherent pulse recombination. Furthermore, the scheme is characterized with attenuated optical reference signals and single-photon detectors, and extended functionality is demonstrated through the use of pulsed reference signals (allowing time-multiplexing of both main and reference signals). Finally, the scheme is used to demonstrate radiofrequency-controlled interference of high-dimensional time-bin entangled states.

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Experimental simulation of loop quantum gravity on a photonic chip

et al. 2023

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The unification of general relativity and quantum theory is one of the fascinating problems of modern physics. One leading solution is Loop Quantum Gravity (LQG). Simulating LQG may be important for providing predictions which can then be tested experimentally. However, such complex quantum simulations cannot run efficiently on classical computers, and quantum computers or simulators are needed. Here, we experimentally demonstrate quantum simulations of spinfoam amplitudes of LQG on an integrated photonics quantum processor. We simulate a basic transition of LQG and show that the derived spinfoam vertex amplitude falls within 4% error with respect to the theoretical prediction, despite experimental imperfections. We also discuss how to generalize the simulation for more complex transitions, in realistic experimental conditions, which will eventually lead to a quantum advantage demonstration as well as expand the toolbox to investigate LQG.

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Quantum tomography of photon states encoded in polarization and picosecond time bins

Cited by 11 publications

References 31 publications

Polarization Sensitive Imaging with Qubits

Polarization Sensitive Imaging with Qubits

Arbitrary Phase Access for Stable Fiber Interferometers

Experimental simulation of loop quantum gravity on a photonic chip

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