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Quantum measurements necessarily disturb the state of physical system. Once we perform a complete measurement, the system undergoes decoherence and loses its coherence. If there is no disturbance, the state retains all of its coherence. It…

Quantum Physics · Physics 2018-10-10 Gautam Sharma , Arun Kumar Pati

An open question of fundamental importance in thermodynamics is how to describe the fluctuations of work for quantum coherent processes. In the standard approach, based on a projective energy measurement both at the beginning and at the end…

Dynamics of zeroth order quantum coherences and preparation of the pseudopure states in homonuclear systems of dipolar coupling spins is closely examined. It has been shown an extreme important role of the non-diagonal part of zeroth order…

Quantum Physics · Physics 2007-05-23 Gregory B. Furman

We propose the notion of quantum coherence for superpositions over states which are not necessarily mutually orthogonal. This anticipatedly leads to a resource theory of non-orthogonal coherence. We characterize free states and free…

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

The well-known two-slit interference is understood as a special relation between observable (localization at the slits) and state (being on both slits). Relation between an observable and a quantum state is investigated in the general case.…

Quantum Physics · Physics 2009-11-11 Fedor Herbut

Quantification of coherence lies at the heart of quantum information processing and fundamental physics. Exact evaluation of coherence measures generally needs a full reconstruction of the density matrix, which becomes intractable for…

Quantum Physics · Physics 2021-06-28 Qi-Ming Ding , Xiao-Xu Fang , Xiao Yuan , Ting Zhang , He Lu

Decoherence is a fundamental obstacle to the implementation of large-scale and low-noise quantum information processing devices. In this work, we suggest an approach for suppressing errors by employing pre-processing and post-processing…

Quantum Physics · Physics 2020-02-25 E. O. Kiktenko , A. S. Mastiukova , A. K. Fedorov

We consider an unambiguous identification of an unknown coherent state with one of two unknown coherent reference states. Specifically, we consider two modes of an electromagnetic field prepared in unknown coherent states alpha_1 and…

Quantum Physics · Physics 2008-12-11 Michal Sedlak , Mario Ziman , Ondrej Pribyla , Vladimir Buzek , Mark Hillery

Quantifying coherence and entanglement is extremely important in quantum information processing. Here, we present numerical and analytical results for the geometric measure of coherence, and also present numerical results for the geometric…

Quantum Physics · Physics 2020-08-27 Zhou Zhang , Yue Dai , Yuli Dong , Chengjie Zhang

Certain pure-state symmetry-protected topological orders (SPT) can be used as a resource for transmitting quantum information. Here, we investigate the ability to transmit quantum information using decohered SPT states, and relate this…

Quantum Physics · Physics 2024-05-10 Zhehao Zhang , Utkarsh Agrawal , Sagar Vijay

Quantum phase estimation is a core task in quantum technologies ranging from metrology to quantum computing, where it appears as a key subroutine in various algorithms. Here, we quantitatively connect the performance of phase estimation…

Quantum Physics · Physics 2026-05-11 Felix Ahnefeld , Thomas Theurer , Martin B. Plenio

How to manage coherence as a continuous variable quantum resource is still an open question. We face this situation from the very definition of incoherent states in quadrature basis. We apply several measures of coherence for some physical…

Quantum Physics · Physics 2023-07-18 Laura Ares , Alfredo Luis

We study an optimized measurement that discriminates two mixed quantum states with maximum confidence for each conclusive result, thereby keeping the overall probability of inconclusive results as small as possible. When the rank of the…

Quantum Physics · Physics 2009-11-13 Ulrike Herzog

We show that quantum computation can be performed in a system at thermal equilibrium if a spontaneous symmetry breaking occurs. The computing process is associated to the time evolution of the statistical average of the qubit coherence…

Statistical Mechanics · Physics 2007-05-23 F. de Pasquale , S. M. Giampaolo

Quantifying coherence is a key task in both quantum mechanical theory and practical applications. Here, a reliable quantum coherence measure is presented by utilizing the quantum skew information of the state of interest subject to a…

Quantum Physics · Physics 2017-05-03 Chang-shui Yu

In the quantitative theory of quantum coherence, the amount of coherence for given states can be meaningfully discussed only when referring to a preferred basis. One of the objections to this quantification is that the amount of coherence…

Quantum Physics · Physics 2024-12-11 Zhi-Xiang Jin , Yuan-Hong Tao , Bing Yu , Shao-Ming Fei

Coherent states provide an appealing method to reconstruct efficiently a pure state of a quantum mechanical spin s. A Stern-Gerlach apparatus is used to measure (4s+1) expectations of projection operators on appropriate coherent states in…

Quantum Physics · Physics 2007-05-23 Jean-Pierre Amiet , Stefan Weigert

Quantum operations with indefinite causal order (ICO) represent a framework in quantum information processing where the relative order between two events can be indefinite. In this paper, we investigate whether sensing and computation, two…

Quantum Physics · Physics 2026-02-12 Ivana Nikoloska

The usual way to reveal properties of an unknown quantum state, given many copies of a system in that state, is to perform measurements of different observables and to analyze the measurement results statistically. Here we show that the…

Quantum Physics · Physics 2014-11-25 Seth Lloyd , Masoud Mohseni , Patrick Rebentrost