Various measures have been suggested recently for quantifying the coherence of a quantum state with respect to given basis. We first use two these, ${l}_{1}$-norm and relative entropy measures, investigate tradeoffs between coherences mutually unbiased bases. Results include relations coherence, uncertainty, purity; tight general bounds restricting bases; an exact complementarity relation qubit coherences. further define average state. For measure this is related natural ``coherence radius''...

Recent progress and future possibilities for EPR steering are presented, highlighting practical applications experimental aspects in multipartite, high-dimensional, atomic macroscopic systems.

The authors demonstrate that, under mild measurement assumptions, two qubits cannot both be recycled to generate Bell nonlocality between multiple independent observers on each side. also derive corresponding ``one-sided monogamy relations'' that rule out two-sided recycling for a wide range of parameters and propose possible experimental test.

Multipartite entanglement is an indispensable resource in quantum communication and computation, however, it a challenging task to faithfully quantify this global property of multipartite systems. In work, we study the concurrence fill, which admits geometric interpretation measure genuine tripartite for three-qubit system [S. Xie {\it et al.}, Phys. Rev. Lett. \textbf{127}. 040403 (2021)]. First, use well-known three-tangle bipartite reformulate quantifier all pure states. We then construct...

The quantum steering ellipsoid can be used to visualize 2-qubit states, and thus provides a generalization of the Bloch picture for single qubit. Recently, monogamy relation volumes ellipsoids has been derived pure 3-qubit states shown stronger than celebrated Coffman-Kundu-Wootters inequality. We first demonstrate close connection between this volume classification under stochastic local operations classical communication. then show that does not hold general mixed derive weaker such...

In a measurement-device-independent or quantum-refereed protocol, referee can verify whether two parties share entanglement Einstein-Podolsky-Rosen (EPR) steering without the need to trust either of their devices. The for trusting party is substituted by quantum channel between and that party, through which encodes measurements be performed on party's subsystem in set nonorthogonal states. this Letter, an EPR-steering inequality adapted as witness, trust-free experimental verification higher...

Quantum properties, such as entanglement and coherence, are indispensable resources in various quantum information processing tasks. However, there still lacks an efficient scalable way to detecting these useful features, especially for high-dimensional multipartite systems. In this work, we exploit the convexity of samples without desired features design unsupervised machine learning method detect presence anomalies. Particularly, context detection, propose a complex-valued neural network...

There is currently much interest in the recycling of entangled systems, for use quantum information protocols by sequential observers. In this work, we study generation Bell nonlocality via one or both components two-qubit states. We first give a description two-valued qubit measurements terms measurement bias, strength, and reversibility, derive useful tradeoff relations between them. Then, one-sided monogamy unbiased observables that strengthen recent conjecture Cheng et al. [Phys. Rev. A...

We present a faithful geometric picture for genuine tripartite entanglement of discrete, continuous, and hybrid quantum systems.We first show that the triangle relation E α i|jk ≤ j|ik + k|ij holds all subadditive bipartite measure E, permutations under parties i, j, k, ∈ [0, 1], pure states.It provides interpretation bipartition entanglement, measured by , corresponds to side triangle, which area with (0, 1) is nonzero if only underlying state genuinely entangled.Then, we rigorously prove...

We report the discovery of two new invariants for three-qubit states which, similarly to three-tangle, are invariant under local unitary transformations and permutations parties. These quantities have a direct interpretation in terms anisotropy pairwise spin correlations. Applications include universal ordering quantum correlation measures pure states; trade-off relations anisotropy, three-tangle Bell nonlocality; strong monogamy inequalities, Einstein-Podolsky-Rosen steering geometric...

The set of all qubit states that can be steered to by measurements on a correlated is predicted form an ellipsoid---called the quantum steering ellipsoid---in Bloch ball. This ellipsoid provides simple visual characterization initial two-qubit state, and various aspects entanglement are reflected in its geometric properties. We experimentally verify these properties via many different polarization-entangled photonic states. Moreover, for pure three-qubit states, volumes two ellipsoids...

Quantum information technologyQuantum technology utilizes physical systems at the microscopic level, such as photon, atom, ion, and superconducting, to accomplish information-processing tasks that are impossible for classical macroscopic world.During past decade, significant process has been achieved in pursuit of quantum into practical applications, generating great research interest from various domains, with potential radically change our infrastructure [1][2][3].The principle mechanics...

Abstract Whether the observables of a physical system admit real values is fundamental importance to deep understanding nature. In this work, we report device-independent experiment confirm that joint reality two on single two-level incompatible with assumption operational completeness, which strictly weaker than preparation noncontextuality. We implement trapped <?CDATA $^{171}\textrm{Yb}^{+}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi...

The quantum steering ellipsoid visualizes the set of all qubit states that can be steered by measuring on another correlated in Bloch picture. Together with local reduced states, it provides a faithful geometric characterization underlying two-qubit state so almost nonclassical features reflected its properties. Consequently, various types ellipsoids different properties form an zoo, which, this paper, is experimentally verified via measurements many polarization-path photonic states. By...

Reconstructing the state of quantum many-body systems is fundamental importance in information tasks, but extremely challenging due to curse dimensionality. In this work, we present an efficient tomography protocol that combines state-factored with eigenvalue mapping address rank-deficient issue and incorporates a momentum-accelerated gradient descent algorithm speed up optimization process. We implement extensive numerical experiments demonstrate our factored efficiently mitigates problem...

To investigate the erosion mechanism and model of ultra-high pressure (200 MPa) water jet on grade–A marine steel with different curvatures. The was induced by plunger pump. dynamic strain collected gauge during impact to explore mechanical effect. microstructure analyzed using three-dimensional topography a scanning electron microscope. results show that average microstrains samples curvature 1/4 m−1, 3/4 5/4 m−1 impacted are 707, 952 1053, respectively, amplitudes 300∼700, 300–600 300–560...

Ultra sensitive detection and high precision measurement of magnetic fields have been great importance for both fundamental physics practical applications. Recent developments in the technology atomic magnetometers enabled spin-exchange relaxation free (SERF) as most devices detecting measuring static or quasi-static fields. In this paper, we analyze effect prominent mechanism (i.e., spin-destruction collisions) on SERF magnetometers. For fields, it is explicitly demonstrated how collisions...

Entanglement lies at the heart of quantum mechanics, and has been identified an essential resource for diverse applications in information. If entanglement could be verified without any trust devices observers, i.e., a device-independent (DI) way, then unconditional security can guaranteed various information tasks. In this work, we propose experimental-friendly DI protocol to certify presence entanglement, based on Einstein-Podolsky-Rosen (EPR) steering. We first establish verification...

It is challenging to identify the state of many-body quantum systems, as recovering density matrices underlying typically requires computational resources scale exponentially system size. In this work, we introduce variational diffusion model (VDM) efficiently learn high-dimensional distributions with high fidelity, which essential realize fast reconstruction states. We build up VDM suitable for dealing samples, and then perform numerical experiments test our other autoregressive models,...

We experimentally test the recently predicted anisotropic invariance properties of pure three-qubit states, via generation and measurement polarisation-path entangled states. These do not require aligned reference frames can be determined from measurements on any two qubits. They have several applications, such as a universal ordering pairwise quantum correlations, strong monogamy relations for Bell inequalities steering, complementarity relation nonlocality versus 3-tangle, some which we...

Abstract Entangling gates are important for the generation of entanglement in quantum communicational and computational tasks. In this work, we propose an efficient protocol to realize multi-qubit entangling with high fidelity Rydberg atoms. Particularly, apply technique soft control design off-resonant pulses such that atoms driven ground-state subspace via unconventional pumping. Thus, our scheme is insensitive decay effect as all only virtually excited. Moreover, Gaussian temporal...

The entropy of a quantum state measures the information or uncertainty contained in system and plays crucial role theory. Many entropic properties, such as subadditivity, have been studied for discrete with finite-dimensional space, while much less is explored infinite-dimensional system. In this work, we study properties continuous that models collection Gaussian modes fields. particular, identify parameter range Rényi, Tsallis, Unified entropies states they are additive, subadditive,...