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Quantum state tomography and other measures of the global properties of a quantum state are indispensable tools in understanding many body physics through quantum simulators. Unfortunately, the number of experimental measurements of the…

Quantum Physics · Physics 2021-06-16 Yariv Yanay , Charles Tahan

The distinction between pure states and mixed states is a kernel ingredient of what is considered to be the standard formulation of quantum mechanics and plays today a kernel role in foundational debates about the meaning of quantum…

History and Philosophy of Physics · Physics 2024-11-01 Christian de Ronde , César Massri

We demonstrate that the task of determining an unknown quantum state can be accomplished efficiently by making a sequential measurement of two observables $\hat{A}$ and $\hat{B}$, provided that the two observables are chosen in such a way…

Quantum Physics · Physics 2013-10-22 Antonio Di Lorenzo

The fields of precision timekeeping and spectroscopy increasingly rely on optical frequency comb interferometry. However, comb-based measurements are not described by existing quantum theory because they exhibit both large mode mismatch and…

Quantum Physics · Physics 2024-04-02 Noah Lordi , Eugene J. Tsao , Alexander J. Lind , Scott A. Diddams , Joshua Combes

Coherence and correlation are key features of the quantum system. Quantifying these quantities are astounding task in the framework of resource theory of quantum information processing. In this article, we identify an affinity-based metric…

Quantum Physics · Physics 2021-02-11 R. Muthuganesan , V. K. Chandrasekar , R. Sankaranarayanan

We reveal that quadrature squeezing can result in significantly better quantum-estimation performance with quantum heterodyne detection (of H. P. Yuen and J. H. Shapiro) as compared to quantum homodyne detection for Gaussian states, which…

Quantum Physics · Physics 2015-10-19 Jaroslav Rehacek , Yong Siah Teo , Zdenek Hradil , Sascha Wallentowitz

A review of the tomographic-probability representation of classical and quantum states is presented. The tomographic entropies and entropic uncertainty relations are discussed in connection with ambiguities in the interpretation of the…

Quantum Physics · Physics 2015-06-11 Margarita A. Man'ko , Vladimir I. Man'ko

We define a positive operator valued measure $E$ on $[0,2\pi]\times R$ describing the measurement of randomly sampled quadratures in quantum homodyne tomography, and we study its probabilistic properties. Moreover, we give a mathematical…

Mathematical Physics · Physics 2015-05-13 P. Albini , E. De Vito , A. Toigo

It has been known that all bipartite pure quantum states can be certified by quantum self-testing, i.e., any such states can be pinned down completely based on the statistics produced by local quantum measurements. A notable feature of…

Quantum Physics · Physics 2024-12-13 Lijinzhi Lin , Zhenyu Chen , Xiaodie Lin , Zhaohui Wei

Quantum operations describe any state change allowed in quantum mechanics, including the evolution of an open system or the state change due to a measurement. In this letter we present a general method based on quantum tomography for…

Quantum Physics · Physics 2009-11-06 G. M. D'Ariano , P. Lo Presti

In this paper, we consider the generalized measurement where one particular quantum signal is unambiguously extracted from a set of non-commutative quantum signals and the other signals are filtered out. Simple expressions for the maximum…

Quantum Physics · Physics 2009-11-10 Masahiro Takeoka , Masashi Ban , Masahide Sasaki

Tracking the dynamics of a quantum system is conventionally achieved by monitoring the system continuously in time and filtering the information contained in measurement records via the causal quantum trajectory approach. However, in…

Correlations obtained from sequences of measurements have been employed to distinguish among different physical theories or to witness the dimension of a system. In this work we show that they can also be used to establish semi-device…

Quantum Physics · Physics 2020-10-23 Cornelia Spee

Entanglement and coherence are fundamental properties of quantum systems, promising to power near future quantum technologies, such as quantum computation, quantum communication and quantum metrology. Yet, their quantification, rather than…

I propose an approach to adaptive homodyne detection of digitally modulated quantum optical pulses in which the phase of the local oscillator is chosen to maximize the average information gain, i.e., the mutual information, at each step of…

Quantum Physics · Physics 2007-05-23 Igor Bargatin

The concept of quantum coherence, including various ways to quantify the degree of coherence with respect to the prescribed basis, is currently the subject of active research. The complementarity of quantum coherence in different bases was…

Quantum Physics · Physics 2017-09-08 Alexey E. Rastegin

Decoherence is the process via which quantum superpositions states are reduced to classical mixtures. Decoherence has been predicted for relativistically accelerated quantum systems, however examples to date have involved restricting the…

Quantum Physics · Physics 2019-01-16 Daiqin Su , Timothy C. Ralph

We analyze homodyne detection of macroscopically bright multimode nonclassical states of light and propose their application in quantum communication. We observe that the homodyne detection is sensitive to a mode-matching of the bright…

Quantum Physics · Physics 2015-11-30 Vladyslav C. Usenko , Laszlo Ruppert , Radim Filip

The thermodynamic uncertainty relation posits that higher thermodynamic costs are essential for a system to function with greater precision. Recent discussions have expanded thermodynamic uncertainty relations beyond classical…

Quantum Physics · Physics 2023-12-13 Yoshihiko Hasegawa

A generic model of measurement device which is able to directly measure commonly used quantum-state characteristics such as fidelity, overlap, purity and Hilbert-Schmidt distance for two general uncorrelated mixed states is proposed. In…

Quantum Physics · Physics 2009-11-07 Radim Filip