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Related papers: Ancilla-free continuous-variable SWAP test

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Efficient overlap estimation of high-dimensional quantum states is an important task in quantum information and a core element in computational speedups of quantum machine learning. Here we experimentally demonstrate the SWAP test that…

Quantum Physics · Physics 2021-03-19 Chi-Huan Nguyen , Ko-Wei Tseng , Gleb Maslennikov , H. C. J. Gan , Dzmitry Matsukevich

Loss of inputs can be detrimental to the security of quantum position verification (QPV) protocols, as it may allow attackers to not answer on all played rounds, but only on those they perform well on. In this work, we study…

Quantum Physics · Physics 2022-08-11 Rene Allerstorfer , Harry Buhrman , Florian Speelman , Philip Verduyn Lunel

We study the estimation of the overlap between two unknown pure quantum states of a finite dimensional system, given $M$ and $N$ copies of each type. This is a fundamental primitive in quantum information processing that is commonly…

Quantum estimation of parameters defining open-system dynamics may be enhanced by using ancillas that are entangled with the probe but are not submitted to the dynamics. Here we consider the important problem of estimation of transmission…

Quantum Physics · Physics 2024-03-04 Jiaxuan Wang , Ruynet. L. de Matos Filho , Girish S. Agarwal , Luiz Davidovich

We present a scheme to conditionally engineer an optical quantum system via continuous-variable measurements. This scheme yields high-fidelity squeezed single photon and superposition of coherent states, from input single and two photon…

Photonics represents one of the most promising approaches to large-scale quantum computation with millions of qubits and billions of gates, owing to the potential for room-temperature operation, high clock speeds, miniaturization of…

Quantum Physics · Physics 2025-07-16 Paul Renault , Patrick Yard , Raphael C. Pooser , Miller Eaton , Hussain Asim Zaidi

Physical-level noise on traveling bosonic modes remains a critical bottleneck for scalable quantum information processing. We show that for any single-mode bosonic code (qumode) corrupted by thermal or Gaussian displacement noise at loss…

We explore optical quantum engineering of phase-parameterized continuous-variable (CV) probe states to exploit nonclassical light to solve the problem of precise phase estimation. The optical interferometer consists of a single beam…

Quantum Physics · Physics 2026-03-11 Mikhail S. Podoshvedov , Sergey A. Podoshvedov

Preparing quantum samples (QSAMPLES), coherent encodings of stationary distributions of reversible Markov chains, is a fundamental primitive in quantum sampling, particularly for quantum simulated annealing. A central limitation of existing…

Quantum Physics · Physics 2026-05-25 Nicholas Zhao

Robust continuous-variable (CV) quantum information processing requires correcting realistic errors in bosonic systems, but all existing schemes rely on auxiliary Gottesman-Kitaev-Preskill (GKP) states which the preparation and operation…

Quantum Physics · Physics 2026-04-09 Negin Razian , En-Jui Chang , Hoi-Kwan Lau

Complete and precise characterization of a quantum dynamical process can be achieved via the method of quantum process tomography. Using a source of correlated photons, we have implemented several methods investigating a wide range of…

While continuous-variable (CV) quantum systems are believed to be more efficient for quantum sensing and metrology than their discrete-variable (DV) counterparts due to the infinite spectrum of their native operators, our toolkit of…

Quantum Physics · Physics 2025-01-10 Xi Lu , Bojko N. Bakalov , Yuan Liu

By interpreting the well-known, qualitative criteria for the existence of quantum error correction (QEC) codes by Knill and Laflamme from a quantitative perspective, we propose a figure of merit for assessing a QEC scheme based on the…

Quantum Physics · Physics 2013-03-05 Ricardo Wickert , Peter van Loock

Continuous-Variable (CV) devices are a promising platform for demonstrating large-scale quantum information protocols. In this framework, we define a general quantum computational model based on a CV hardware. It consists of vacuum input…

Quantum Physics · Physics 2019-02-06 Tom Douce , Damian Markham , Elham Kashefi , Peter van Loock , Giulia Ferrini

Quantum entanglement is an essential resource for quantum technologies, and the controlled swap test provides a versatile tool for its detection and quantification. Here, we propose a SWAP-based entanglement witness that applies to…

Quantum Physics · Physics 2025-12-24 Sebastiano Guaraldo , Sonia Mazzucchi , Alessio Baldazzi , Stefano Azzini , Lorenzo Pavesi

This topical review introduces the theoretical and experimental advances in continuous-variable (CV) --- i.e., qumode-based in lieu of qubit-based --- large-scale, fault-tolerant quantum computing and quantum simulation. An introduction to…

Quantum Physics · Physics 2020-01-08 Olivier Pfister

Numerical simulation of continuous variable quantum state preparation is a necessary tool for optimization of existing quantum information processing protocols. A powerful instrument for such simulation is the numerical computation in the…

Quantum Physics · Physics 2022-10-10 Jan Provazník , Radim Filip , Petr Marek

In hybrid circuit QED architectures containing both ancilla qubits and bosonic modes, a controlled beam splitter gate is a powerful resource. It can be used to create (up to a controlled-parity operation) an ancilla-controlled SWAP gate…

Quantum Physics · Physics 2026-05-08 Iivari Pietikäinen , Ondřej Černotík , Shruti Puri , Radim Filip , S. M. Girvin

Measurement-based quantum error correction relies on the ability to determine the state of a subset of qubits (ancillae) within a processor without revealing or disturbing the state of the remaining qubits. Among neutral-atom based…

We demonstrate mid-circuit measurements in a neutral atom array by shelving data qubits in protected hyperfine-Zeeman sub-states while non-destructively measuring an ancilla qubit. Measurement fidelity was enhanced using microwave repumping…

Quantum Physics · Physics 2024-05-31 T. M. Graham , L. Phuttitarn , R. Chinnarasu , Y. Song , C. Poole , K. Jooya , J. Scott , A. Scott , P. Eichler , M. Saffman
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