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The Cosmic Distance Duality Relation (CDDR) is a basic relation of standard cosmology. This work tests the CDDR and cosmic transparency using angular diameter distances from DESI DR2, luminosity distances from Pantheon+, and direct…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Xuwei Zhang , Xiaofeng Yang , Yunliang Ren , Shuangnan Chen , Yangjun Shi , Cheng Cheng , Xiaolong He

A bipartite quantum system in a mixed state can exhibit nonclassical correlations, which can go beyond quantum entanglement. While quantum discord is the standard measure of quantifying such general quantum correlations, the nonclassicality…

Quantum Physics · Physics 2017-06-21 Amandeep Singh , Arvind , Kavita Dorai

Coherence is a fundamental resource in quantum information processing, which can be certified by a coherence witness. In order to detect all the coherent states, we introduce a useful concept of coherence witness and structure the set of…

Quantum Physics · Physics 2024-10-29 Xue-Na Zhu , Zhi-Xiang Jin , Gui Bao , Shao-Ming Fei

Quantum Darwinism offers an explanation for the emergence of classical objective features -- those we are used to at macroscopic scales -- from quantum properties at the microscopic level. The interaction of a quantum system with its…

The concept of entanglement witnesses form a useful technique to detect entanglement in realistic quantum devices. Measurement-device-independent nonlinear entanglement witnesses (MDI-NEWs) are a kind of entanglement witnesses which…

Quantum Physics · Physics 2023-12-01 Kornikar Sen , Chirag Srivastava , Ujjwal Sen

We investigate whether paradigmatic measurements for quantum state tomography, namely mutually unbiased bases and symmetric informationally complete measurements, can be employed to certify quantum correlations. For this purpose, we…

We test the cosmic distance duality relation (CDDR) using two model-independent methods. Method I is based on the PAge parametrization, which characterizes the expansion history in terms of the cosmic age. Parametrizations of possible CDDR…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-10 Xing Wu

Photon loss represents a major challenge for the implementation of quantum communication protocols with untrusted devices, e.g. in the device-independent (DI) or semi-DI approaches. Determining critical loss thresholds is usually done in…

Quantum Physics · Physics 2024-12-30 Michele Masini , Marie Ioannou , Nicolas Brunner , Stefano Pironio , Pavel Sekatski

We investigate entanglement detection when the local measurements only nearly correspond to those intended. This corresponds to a scenario in which measurement devices are not perfectly controlled, but nevertheless operate with bounded…

Quantum Physics · Physics 2022-06-22 Simon Morelli , Hayata Yamasaki , Marcus Huber , Armin Tavakoli

The universality of quantum theory has been questioned ever since it was proposed. Key to this long-unsolved question is to test whether a given physical system has non-classical features. Here we connect recently proposed witnesses of…

We introduce a measure of the compatibility between quantum states--the likelihood that two density matrices describe the same object. Our measure is motivated by two elementary requirements, which lead to a natural definition. We list some…

Quantum Physics · Physics 2009-11-07 David Poulin , Robin Blume-Kohout

Generation of spatially inhomogeneously polarized (SIP) beams due to polarization spatial mode nonseparability is demonstrated using a polarization Sagnac interferometer. Counter propagating horizontal (H) and vertical (V) polarized…

Optics · Physics 2015-06-24 C. T. Samlan , Nirmal K. Viswanathan

The certification of quantum nonlocality, which has immense significance in architecting device-independent technologies, confronts severe experimental challenges. Detection loophole, originating from the unavailability of perfect…

Quantum Physics · Physics 2024-05-21 Subhendu B. Ghosh , Snehasish Roy Chowdhury , Ranendu Adhikary , Arup Roy , Tamal Guha

It is a well-known fact that measurement incompatibility is a necessary resource to generate nonlocal correlations in usual Bell scenario that typically involves single quantum source. We can provide with some contrasting findings if we…

Quantum Physics · Physics 2025-08-15 Kaushiki Mukherjee , Biswajit Paul

Using the exact Lemaitre-Bondi-Tolman solution with a non-vanishing cosmological constant $\Lambda$, we investigate how the presence of a local spherically-symmetric inhomogeneity can affect apparent cosmological observables, such as the…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-01 Antonio Enea Romano , Misao Sasaki , Alexei A. Starobinsky

Quantum metrology utilizes entanglement for improving the sensitivity of measurements. Up to now the focus has been on the measurement of just one out of two non-commuting observables. Here we demonstrate a laser interferometer that…

We look into the task of differentiating between any two quantum channels and reconstructing them from the obtained measurement statistics with possibly limited information about the experimental set-up. We employ the communication matrix…

Quantum Physics · Physics 2025-11-19 Samgeeth Puliyil , Leevi Leppäjärvi , Mário Ziman

In quantum information and communication one looks for the non-classical features like interference and quantum correlations to harness the true power of composite systems. We show how the concept akin to interference is, in fact,…

Quantum Physics · Physics 2015-08-11 Lin Zhang , Arun Kumar Pati , Junde Wu

One of the basic distinctions between classical and quantum mechanics is the existence of fundamentally incompatible quantities. Such quantities are present on all levels of quantum objects: states, measurements, quantum channels, and even…

Quantum Physics · Physics 2021-06-16 Erkka Haapasalo , Tristan Kraft , Nikolai Miklin , Roope Uola

Given a pair of isolated devices that accept random binary inputs and return binary outputs, a user can deduce from the observed data alone if the underlying mechanism can be explained classically. Bell's theorem further states that a…

Quantum Physics · Physics 2026-05-21 Kuntal Sengupta , Lewis Wooltorton