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Measurements can be considered as a genuine example of processes that crush quantum coherence. In the case of an observable with degeneracy, the formulations of L\"{u}ders and von Neumann are known. These pictures postulate the two…

Quantum Physics · Physics 2019-04-23 Alexey E. Rastegin

Quantum coherence, the ability of a quantum system to be in a superposition of orthogonal quantum states, is a distinct feature of the quantum mechanics, thus marking a deviation from classical physics. Coherence finds its applications in…

Quantum Physics · Physics 2023-01-18 Najmeh Etehadi Abari , Andrey Rakhubovsky , Radim Filip

We demonstrate the simple and deep equivalence between quantum coherence and nonclassicality and the definite way in which they determine metrological resolution. Moreover, we define a coherence observable consistent with a classical…

Quantum Physics · Physics 2021-09-10 Laura Ares , Alfredo Luis

Quantum coherence is a basic feature of quantum physics. Combined with tensor product structure of state space, it gives rise to the novel concepts such as entanglement and quantum correlations, which play a crucial role in quantum…

Quantum Physics · Physics 2017-04-18 Kaifeng Bu , Asutosh Kumar , Lin Zhang , Junde Wu

Detecting coherence transfer in complex quantum networks can be challenging due to uncharacterized experimental conditions and limited system access. Here, we use static and dynamic coherence features to introduce a nonlinear criterion for…

The interference observed for a quanton, traversing more than one path, is believed to characterize its wave nature. Conventionally, the sharpness of interference has been quantified by its visibility or contrast, as defined in optics.…

Quantum Physics · Physics 2019-06-21 Tabish Qureshi

The conventional coherence is defined with respect to a fixed orthonormal basis, i.e., to a von Neumann measurement. Recently, generalized quantum coherence with respect to general positive operator-valued measurements (POVMs) has been…

Quantum Physics · Physics 2022-01-04 Jianwei Xu , Lin Zhang , Shao-Ming Fei

A quantum system's state is identified with a density matrix. Though their probabilistic interpretation is rooted in ensemble theory, density matrices embody a known shortcoming. They do not completely express an ensemble's physical…

Quantum Physics · Physics 2021-06-30 Fabio Anza , James P. Crutchfield

We report an algorithm, based on quantum optics formulation, where a coherent state is used as the elementary quantum resource for the image representation. We provide an architecture with constituent optical elements in linear order with…

Quantum Physics · Physics 2024-10-01 Vivek Mehta , Sonali Jana , Utpal Roy

A direct classical analog of the quantum dynamics of intrinsic decoherence in Hamiltonian systems, characterized by the time dependence of the linear entropy of the reduced density operator, is introduced. The similarities and differences…

Quantum Physics · Physics 2009-11-10 Jiangbin Gong , Paul Brumer

We aim to bridge the gap between quantum coherence, quantum correlations, and nonequilibrium quantum transport in a quantum double-dot (QDD) system interacting with fermionic reservoirs. The system-reservoir coupling is modeled using a…

Quantum Physics · Physics 2025-02-18 Saikumar Krithivasan , Thingujam Yaiphalemba Meitei , Arijit Sen , Md Manirul Ali

Quantum principal component analysis (QPCA) ignited a new development toward quantum machine learning algorithms. Initially showcasing as an active way for analyzing a quantum system using the quantum state itself, QPCA also found potential…

Quantum Physics · Physics 2025-01-15 Nhat A. Nghiem

Coherent coupling between spatially separated systems has long been explored as a necessary requirement for quantum information and cryptography. Recent discoveries suggest such phenomena appear in a much wider range of processes, including…

Optics · Physics 2015-03-03 Jonathan O Tollerud , Christopher R Hall , Jeffrey A Davis

Wave--particle duality is a cornerstone of quantum mechanics, traditionally formulated under definite causal order. We investigate how complementarity is modified when the temporal order of operations is coherently superposed, as in the…

Quantum Physics · Physics 2026-03-31 Mohd Asad Siddiqui , Md Qutubuddin , Tabish Qureshi

Quantum coherence represented by a superposition of energy eigenstates is, together with energy, an important resource for quantum technology and thermodynamics. Energy and quantum coherence however, can be complementary. The increase of…

Quantum Physics · Physics 2022-11-17 Mariia Gumberidze , Michal Kolář , Radim Filip

The non-increasing behavior of quantum coherence during any incoherent quantum process such as an incoherent quantum channel occurring in a noisy environment is a general property of quantum coherence. We address that the concatenation of…

Quantum Physics · Physics 2021-12-22 Durgun Duran

Quantum coherent superpositions of states with different energies, i.e., states with coherence with respect to energy basis, are important resource for modern quantum technologies. States with small coherence can be obtained either…

Quantum Physics · Physics 2022-11-17 Mariia Gumberidze , Michal Kolář , Radim Filip

We present a family of coherence quantifiers based on the generalized $\alpha-z-$relative R$\acute{e}$nyi entropy. These quantifiers satisfy all the standard criteria for well-defined measures of coherence, and include some existing…

Quantum Physics · Physics 2019-05-07 Xue-Na Zhu , Zhi-Xiang Jin , Shao-Ming Fei

As an analogy of fully entangled fraction in the framework of entanglement theory, we have introduced the notion of quantum coherence fraction $C_{\mathcal{F}}$, which quantifies the closeness between a given state and the set of maximally…

Quantum Physics · Physics 2019-09-25 Yao Yao , Dong Li , C. P. Sun

The impact of coherence on the nonlinear optical response and stationary transport is studied in quantum cascade laser structures. Nonequilibrium effects such as pump-probe signals, the spatio-temporally resolved electron density evolution,…

Mesoscale and Nanoscale Physics · Physics 2009-05-12 C. Weber , A. Wacker , A. Knorr