Article
Multidisciplinary Sciences
Laure Mercier de Lepinay, Caspar F. Ockeloen-Korppi, Matthew J. Woolley, Mika A. Sillanpaa
Summary: The study demonstrates a method to measure an oscillator without quantum back-action by constructing an effective oscillator. By using two micromechanical oscillators, it was possible to achieve a quantum mechanics-free subsystem and measure two collective quadratures with an 8-decibel improvement while evading quantum back-action. The direct verification of quantum entanglement of the two oscillators was also achieved by measuring the Duan quantity 1.4 decibels below the separability bound.
Article
Quantum Science & Technology
Yaxue Liu, Lili Yang, Donghua Yan
Summary: In this paper, an entanglement measure based on Hellinger distance for bipartite quantum states is proposed and shown to satisfy the necessary conditions of entanglement measure. Furthermore, a relation between the given entanglement measure and quantum coherence measure based on Hellinger distance is obtained.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Optics
Namrata Shukla, Ranjan Modak, Bhabani Prasad Mandal
Summary: We establish an uncertainty relation for PT-invariant non-Hermitian quantum systems of arbitrary finite dimensions using a specific inner product framework. This construction is motivated by good observables, which are a broader class of operators. We demonstrate that the cumulative gain in quantum Fisher information obtained by measuring two good observables in these non-Hermitian systems surpasses that in their Hermitian counterparts. The preference for minimum uncertainty states near the exceptional point confirms the effectiveness of intelligent or simultaneous non-Hermitian quantum sensors.
Article
Quantum Science & Technology
Zhi-Xiang Jin, Shao-Ming Fei, Xianqing Li-Jost, Cong-Feng Qiao
Summary: A generalized definition of monogamy relation for entanglement measures is provided, and a monogamy equality is presented based on the monogamy weight. The significance and advantages of these relations are further demonstrated using concurrence as an example. It is shown that monogamy relations can be recovered by considering multiple copies of states for every non-additive entanglement measure that violates the inequalities. Additionally, it is demonstrated that such relations for tripartite states can be generalized to multipartite systems.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Article
Physics, Multidisciplinary
Qing-Yun Zhou, Xiao-Gang Fan, Fa Zhao, Dong Wang, Liu Ye
Summary: This research proves an inequality relation between entanglement of formation and first-order coherence of two-qubit states, with the upper bound of this inequality reached by two-qubit pure states. The complementarity between entanglement of formation and first-order coherence is intuitively verified through a large number of randomly generated states. The maximum accessible coherence of two-qubit states is determined, providing a reliable theoretical basis for the conversion of these two quantum resources.
Article
Materials Science, Multidisciplinary
Chengkang Zhou, Meng -Yuan Li, Zheng Yan, Peng Ye, Zi Yang Meng
Summary: This study employs strange correlators to detect 2D SSPT phases protected by subsystem symmetries and performs quantum Monte Carlo simulation. The research finds that strange correlators exhibit long-range correlations in the SSPT phase and characterizes the topological phase transition and spatial anisotropy by defining strange order parameters.
Article
Physics, Multidisciplinary
Yun Cao, Dong Wang, Xiao-Gang Fan, Fei Ming, Zhang-Yin Wang, Liu Ye
Summary: This study explores the complementary relationship between quantum entanglement and the entropic uncertainty relation, revealing an inequality relation between them where greater uncertainty leads to weaker entanglement in the probed system. By using randomly generated states to verify the results, it is claimed that the entropic uncertainty relation can be used to estimate quantum entanglement.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Hazhir Dolatkhah, Abolhassan Mohammadi, Soroush Haseli
Summary: This work studies the relationship between entropic uncertainty relation and the shareability of quantum discord. The research provides an upper bound for the shareability of quantum discord in a composite system using the tripartite quantum-memory-assisted entropic uncertainty relation. It is also shown that monogamy of quantum discord can be expressed for a specific class of tripartite states, and a generalized upper bound for the shareability of quantum discord for multipartite states is derived.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Jordan Cotler, Nicholas Hunter-Jones, Daniel Ranard
Summary: In this study, we investigate the fluctuations of subsystem entropies in closed quantum many-body systems after thermalization. By combining analytics and numerics, we find that the statistics of entropy fluctuations in quantum systems are significantly different from the classical case. The probability of entropy fluctuations in a subregion is suppressed in the dimension of the Hilbert space of the complementary subregion shortly after thermalization. This suppressions becomes more stringent over time, ultimately depending on the exponential of the Hilbert space dimension. We also estimate the total number of rare fluctuations at large timescales, and find that the Boltzmann brain paradox is largely resolved in quantum many-body systems.
Article
Multidisciplinary Sciences
Saeed Haddadi, Mohammad Reza Pourkarimi, Soroush Haseli
Summary: The newly proposed quantum-memory-assisted entropic uncertainty relation demonstrates the uncertainty principle of quantum mechanics. This relation holds significance for two arbitrary incompatible observables and the uncertainties in the results of two measurements, potentially playing a critical role in the foundations of quantum theory.
SCIENTIFIC REPORTS
(2021)
Article
Multidisciplinary Sciences
Huan-Yu Ku, Chung-Yun Hsieh, Shin-Liang Chen, Yueh-Nan Chen, Costantino Budroni
Summary: The study explores the importance of quantum steering in both theoretical foundations and practical applications. The researchers propose a condition for transforming a steerable resource into another via local filtering, based on the concept of steering equivalent observables (SEO). They provide an efficient method for computing the maximum extractable steerability via local filters and demonstrate its equivalence to the incompatibility of the SEO. Additionally, they investigate the optimal performance of transformation protocols in the single-shot scenario.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Fluids & Plasmas
M. Kliczkowski, R. Swietek, L. Vidmar, M. Rigol
Summary: This article investigates the agreement between the average entanglement entropy of midspectrum eigenstates of quantum-chaotic interacting Hamiltonians and that of random pure states. It is found that the leading terms are identical, but the differences in subleading terms remain unclear. State-of-the-art full exact diagonalization calculations are conducted on clean spin-1/2 XYZ and XXZ chains to determine the maximally chaotic regime. The study reveals that the negative O(1) correction for the average entanglement entropy is slightly larger than that predicted for random pure states, and a simple expression is derived to describe the ν dependence of the O(1) deviation.
Article
Astronomy & Astrophysics
He Wang, Jin Wang
Summary: This study quantifies quantum correlations between two accelerated detectors coupled to a scalar field in a cavity, considering the effects of acceleration-induced thermal bath. The research reveals that entanglement decreases to zero as accelerations increase, whereas mutual information can be amplified. Quantum correlations decay when accelerations are in opposite directions, but larger quantum correlations can appear in certain nonequilibrium scenarios.
Article
Physics, Multidisciplinary
Qing Liao, Charly Leblanc, Jiahuan Ren, Feng Li, Yiming Li, Dmitry Solnyshkov, Guillaume Malpuech, Jiannian Yao, Hongbing Fu
Summary: This study reports the first experimental measurement of the quantum metric in a non-Hermitian system. The platform under study is an organic microcavity with exciton-polariton eigenstates, demonstrating exceptional points. The measurement shows the divergence of the quantum metric and determines the scaling exponent to be n = -1.01 +/- 0.08, consistent with the theoretical description of second-order exceptional points.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Mauricio Reis, Adelcio C. Oliveira
Summary: In this study, an analysis of the Jaynes-Cummings Model was conducted in parameter spaces, revealing dynamics in different Roughness, Concurrence/Linear Entropy, and Visibility conditions. The inclusion of Roughness in the analysis helps identify non-classicality points not easily perceived by traditional analysis, with the parameter space being almost completely occupied when the dispersive term is small and concentrated in regions of less roughness and purity as the dispersive coefficient increases.
JOURNAL OF COMPUTATIONAL ELECTRONICS
(2021)
