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Related papers: Is it Gaussian? Testing bosonic quantum states

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In this work we are interested the problem of testing quantum entanglement. More specifically, we study the separability problem in quantum property testing, where one is given $n$ copies of an unknown mixed quantum state $\varrho$ on…

Quantum Physics · Physics 2019-09-11 Costin Bădescu , Ryan O'Donnell

Quantum state tomography, the ability to deduce the state of a quantum system from measured data, is the gold standard for verification and benchmarking of quantum devices. It has been realized in systems with few components, but for larger…

The paper investigated a set of non-Gaussian states generated by measuring the number of particles in one of the modes of a two-mode entangled Gaussian state. It was demonstrated that all generated states depend on two types of parameters:…

Quantum Physics · Physics 2025-01-14 S. B. Korolev , E. N. Bashmakova , T. Yu. Golubeva

The resource-theoretic frameworks for quantum imaginarity have been developed in recent years. Within these frameworks, many imaginarity measures for finite-dimensional systems have been proposed. However, for imaginarity of Gaussian states…

Quantum Physics · Physics 2025-04-14 Ting Zhang , Jinchuan Hou , Xiaofei Qi

All the $n(2n+3)$ mean and covariance parameters of an $n$-mode Gaussian states are expressed in terms of the expectation values of the same number of conjugates of the total number observable. This permits a complete tomography of the…

Quantum Physics · Physics 2016-01-14 K. R. Parthasarathy , Ritabrata Sengupta

We show that the quantum measurement known as the pretty good measurement can be used to identify an unknown quantum state picked from any set of $n$ mixed states that have pairwise fidelities upper-bounded by a constant below 1, given…

Quantum Physics · Physics 2019-11-11 Ashley Montanaro

We show with explicit formulas that one can completely identify an unknown quantum process with only one weakly entangled state; and identify a quantum optical Gaussian process with either one two-mode squeezed state or a few different…

Quantum Physics · Physics 2010-10-05 Xiang-Bin Wang , J. -Z. Hu , Z. -W. Yu , Franco Nori

The pretty good measurement is a fundamental analytical tool in quantum information theory, giving a method for inferring the classical label that identifies a quantum state chosen probabilistically from an ensemble. Identifying and…

Quantum Physics · Physics 2024-09-17 Hemant K. Mishra , Ludovico Lami , Prabha Mandayam , Mark M. Wilde

Verification is a task to check whether a given quantum state is close to an ideal state or not. In this paper, we show that a variety of many-qubit quantum states can be verified with only sequential single-qubit measurements of Pauli…

Quantum Physics · Physics 2018-06-13 Yuki Takeuchi , Tomoyuki Morimae

Here we propose an experimental set-up in which it is possible to measure the entanglement of a two-mode Gaussian state, be it pure or mixed, using only simple linear optical devices. After a proper unitary manipulation of the two-mode…

Quantum Physics · Physics 2015-06-26 Gustavo Rigolin , Marcos C. de Oliveira

Instantaneous quantum computing is a sub-universal quantum complexity class, whose circuits have proven to be hard to simulate classically in the Discrete-Variable (DV) realm. We extend this proof to the Continuous-Variable (CV) domain by…

Quantum Physics · Physics 2017-02-21 T. Douce , D. Markham , E. Kashefi , E. Diamanti , T. Coudreau , P. Milman , P. van Loock , G. Ferrini

A growing cohort of experimental linear photonic networks implementing Gaussian boson sampling (GBS) have now claimed quantum advantage. However, many open questions remain on how to effectively verify these experimental results, as…

Quantum Physics · Physics 2023-08-03 Alexander S. Dellios , Margaret D. Reid , Peter D. Drummond

Generation of high fidelity photonic non-Gaussian states is a crucial ingredient for universal quantum computation using continous-variable platforms, yet it remains a challenge to do so efficiently. We present a general framework for a…

Quantum Physics · Physics 2019-11-06 Daiqin Su , Casey R. Myers , Krishna Kumar Sabapathy

In this article, we study the problem of comparing mixed quantum states: given $n$ unknown mixed quantum states, can one determine whether they are identical or not with an unambiguous quantum measurement? We first study universal…

Quantum Physics · Physics 2015-05-18 Shengshi Pang , Shengjun Wu

Gaussian processes allow for flexible specification of prior assumptions of unknown dynamics in state space models. We present a procedure for efficient Bayesian learning in Gaussian process state space models, where the representation is…

Computation · Statistics 2016-04-18 Andreas Svensson , Arno Solin , Simo Särkkä , Thomas B. Schön

Although the realization of useful quantum computers poses significant challenges, swift progress in emerging quantum technologies is making this goal realistically approachable. In this context, one of the essential resources is quantum…

Quantum Physics · Physics 2022-01-11 Valeria Saggio , Philip Walther

Quantum computers are now on the brink of outperforming their classical counterparts. One way to demonstrate the advantage of quantum computation is through quantum random sampling performed on quantum computing devices. However, existing…

In this paper, the problem of state estimation, in the context of both filtering and smoothing, for nonlinear state-space models is considered. Due to the nonlinear nature of the models, the state estimation problem is generally intractable…

Machine Learning · Statistics 2021-11-24 Jarrad Courts , Adrian Wills , Thomas B. Schön

Quantum state tomography (QST) aims at estimating a quantum state from averaged quantum measurements made on copies of the state. Most quantum algorithms rely on QST at some point and it is a well explored topic in the literature, mostly…

Quantum Physics · Physics 2023-01-18 François Verdeil , Yannick Deville

Quantum systems can be prepared in an infinite continuum of states, but only some of them can be used as resources for quantum technologies. Discerning whether a specific quantum state falls into this class, is often a challenging task. We…

Quantum Physics · Physics 2025-09-11 Šimon Bräuer , Tomáš Opatrný , Petr Marek