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The study of quantum correlations in High-dimensional bipartite systems is crucial for the development of quantum computing. We propose relative entropy as a distance measure of correlations may be measured by means of the distance from the…

Quantum Physics · Physics 2016-04-12 M. Mahdian , M. B. Arjmandi

It is a central fact in quantum mechanics that non-orthogonal states cannot be distinguished perfectly. This property ensures the security of quantum key distribution. It is therefore an important task in quantum communication to design and…

Quantum Physics · Physics 2023-11-27 Lorcan O. Conlon , Falk Eilenberger , Ping Koy Lam , Syed M. Assad

The existence of incompatible measurements, i.e. measurements which cannot be performed simultaneously on a single copy of a quantum state, constitutes an important distinction between quantum mechanics and classical theories. While…

Quantum Physics · Physics 2022-06-22 Krzysztof Mordasewicz , Jędrzej Kaniewski

Entangled many-body states enable high-precision quantum sensing beyond the standard quantum limit. We develop interferometric sensing protocols based on quantum critical wavefunctions and compare their performance with…

Quantum Physics · Physics 2026-01-09 Yinan Chen , Sara Murciano , Pablo Sala , Jason Alicea

Geometric discord, a measure of quantumness of bipartite system, captures minimal nonlocal effects of a quantum state due to locally invariant von Neumann projective measurements. Original version of this measure is suffered by the local…

Quantum Physics · Physics 2019-06-10 R. Muthuganesan , V. K. Chandrasekar

We propose a family of lower bounds for concurrence in quantum systems using mutually unbiased measurements, which prove more effective in entanglement estimation compared to existing methods. Through analytical and numerical examples, we…

Quantum Physics · Physics 2025-04-22 Yu Lu , Meng Su , Zhong-Xi Shen , Hong-Xing Wu , Shao-Ming Fei , Zhi-Xi Wang

We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local projective measurement on the qubit, which is valid for general entropic forms and becomes exact in…

Quantum Physics · Physics 2015-06-22 N. Gigena , R. Rossignoli

We prove tight $\Omega(n^{1/3})$ lower bounds on the quantum query complexity of the Collision and the Set Equality problems, provided that the size of the alphabet is large enough. We do this using the negative-weight adversary method.…

Quantum Physics · Physics 2017-07-31 Aleksandrs Belovs , Ansis Rosmanis

Open quantum systems are governed by both unitary and non-unitary dynamics, with dissipation arising from the latter. Traditional quantum divergence measures, such as quantum relative entropy, fail to account for the non-unitary oriented…

Quantum Physics · Physics 2025-09-23 Tomohiro Nishiyama , Yoshihiko Hasegawa

An indirect quantum state measurement process is under investigation. Common evolution of detector's microscopic part (pointer) and measured system (target) is considered to be nonunitary due to the interaction between pointer and…

Quantum Physics · Physics 2015-06-17 Alexander Trifanov , George Miroshnichenko

We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance (NMR) setup and employing geometric discord, we evaluate the quantum correlations of a…

We study an optimum measurement for quantum state discrimination, which maximizes the probability of correct results when the probability of inconclusive results is fixed at a given value. The measurement describes minimum-error…

Quantum Physics · Physics 2012-09-26 Ulrike Herzog

We derive an analytical expression for the lower bound of the concurrence of mixed quantum states of composite 2xK systems. In contrast to other, implicitly defined entanglement measures, the numerical evaluation of our bound is…

Quantum Physics · Physics 2009-11-10 Artur Lozinski , Andreas Buchleitner , Karol Zyczkowski , Thomas Wellens

Characterizing complexity and criticality in quantum systems requires diagnostics that are both computationally tractable and physically insightful. We apply a measure of quantum state complexity for n-qubit systems, defined as the…

Quantum Physics · Physics 2026-02-10 Imre Varga

We experimentally demonstrate a weak measurement and measurement reversal-based scheme to ameliorate the effects of decoherence due to amplitude damping, on an NMR quantum processor. The weak measurement and measurement reversal processes…

Quantum Physics · Physics 2024-09-20 Gayatri Singh , Akshay Gaikwad , Arvind , Kavita Dorai

Cavity optomechanical (COM) sensors, featuring efficient light-motion couplings, have been widely used for ultra sensitive measurements of various physical quantities ranging from displacements to accelerations or weak forces. Previous…

Quantum Physics · Physics 2024-03-18 Jie Wang , Qian Zhang , Ya-Feng Jiao , Sheng-Dian Zhang , Tian-Xiang Lu , Zhipeng Li , Cheng-Wei Qiu , Hui Jing

Quantum incompatibility, referred as the phenomenon that some quantum measurements cannot be performed simultaneously, is necessary for various quantum information processing tasks, such as nonlocality and steering. When these applications…

Quantum Physics · Physics 2024-11-19 Xiaolin Zhang , Rui Qu , Zehong Chang , Yunlong Wang , Zhenyu Guo , Min An , Hong Gao , Fuli Li , Pei Zhang

We prove concentration bounds for the following classes of quantum states: (i) output states of shallow quantum circuits, answering an open question from [DPMRF22]; (ii) injective matrix product states; (iii) output states of dense…

Quantum Physics · Physics 2023-05-17 Anurag Anshu , Tony Metger

The ability to completely characterize the state of a quantum system is an essential element for the emerging quantum technologies. Here, we present a compressed-sensing inspired method to ascertain any rank-deficient qudit state, which we…

We establish a connection between quantum inequalities (known from quantum field theory on curved spacetimes) and the degree of squeezing in quantum-optical experiments. We prove an inequality which binds the reduction of the electric-field…

Quantum Physics · Physics 2009-11-07 P. Marecki