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We establish a lower bound on the quantum coherence of an arbitrary quantum state in arbitrary dimension, using a noncommutativity estimator of an arbitrary observable of sub-unit norm, where the estimator is the commutator of the…

Quantum Physics · Physics 2022-06-22 Tanaya Ray , Ahana Ghoshal , Arun Kumar Pati , Ujjwal Sen

Our aim is to experimentally study the possibility of distinguishing between quantum sources of randomness--recently proved to be theoretically incomputable--and some well-known computable sources of pseudo-randomness. Incomputability is a…

Quantum Physics · Physics 2009-12-23 Cristian S. Calude , Michael J. Dinneen , Monica Dumitrescu , Karl Svozil

Brakerski et. al [BCM+18] introduced the model of cryptographic testing of a single untrusted quantum device and gave a protocol for certifiable randomness generation. We use the leakage resilience properties of the Learning With Errors…

Quantum Physics · Physics 2022-04-26 Urmila Mahadev , Umesh Vazirani , Thomas Vidick

Our ability to trust that a random number is truly random is essential for fields as diverse as cryptography and fundamental tests of quantum mechanics. Existing solutions both come with drawbacks -- device-independent quantum random number…

A quantum random number generator (QRNG) as a genuine source of randomness is essential in many applications, such as number simulation and cryptography. Recently, a source-independent quantum random number generator (SI-QRNG), which can…

Quantum coherence is a fundamental resource that quantum technologies exploit to achieve performance beyond that of classical devices. A necessary prerequisite to achieve this advantage is the ability of measurement devices to detect…

Device-independent (DI) tests allow to witness and quantify the quantum feature of a system, such as entanglement, without trusting the implementation devices. Although DI test is a powerful tool in many quantum information tasks, it…

Quantum Physics · Physics 2023-09-07 Xingjian Zhang , Yunchao Liu , Xiao Yuan

Randomness is a key feature of quantum physics. Heisenberg's uncertainty principle reveals the existence of an intrinsic noise, usually explored through Gaussian squeezed states. Due to their insufficiency for quantum advantage, the focus…

Quantum Physics · Physics 2025-11-20 Vojtěch Kala , Jiří Fadrný , Michal Neset , Jan Bílek , Petr Marek , Miroslav Ježek

Quantum randomness relies heavily on the accurate characterization of the generator implementation, where the device imperfection or inaccurate characterization can lead to incorrect entropy estimation and practical bias, significantly…

Quantum Physics · Physics 2024-09-12 You-Qi Nie , Hongyi Zhou , Bing Bai , Qi Xu , Xiongfeng Ma , Jun Zhang , Jian-Wei Pan

We propose an alternative framework for quantifying coherence. The framework is based on a natural property of coherence, the additivity of coherence for subspace-independent states, which is described by an operation-independent equality…

Quantum Physics · Physics 2017-01-04 Xiao-Dong Yu , Da-Jian Zhang , G. F. Xu , D. M. Tong

In this paper we propose a quantum random number generator (QRNG) which utilizes an entangled photon pair in a Bell singlet state, and is certified explicitly by value indefiniteness. While "true randomness" is a mathematical impossibility,…

Quantum Physics · Physics 2014-04-01 Alastair A. Abbott , Cristian S. Calude , Karl Svozil

An approach to quantum random number generation based on unambiguous quantum state discrimination (USD) is developed. We consider a prepare-and-measure protocol, where two non-orthogonal quantum states can be prepared, and a measurement…

Coherence is a cornerstone of quantum theory and a prerequisite for the advantage of quantum technologies. In recent work, the notion of coherence with respect to a general quantum measurement (POVM) was introduced and embedded into a…

Quantum Physics · Physics 2021-03-31 Felix Bischof , Hermann Kampermann , Dagmar Bruß

Randomness is an indispensable resource in modern science and information technology. Fortunately, an experimentally simple procedure exists to generate randomness with well-characterized devices: measuring a quantum system in a basis…

Quantum Physics · Physics 2016-08-24 Le Phuc Thinh , Jean-Daniel Bancal , Eduardo Martin-Martinez

Quantum nonlocality can be observed in networks even in the case where every party can only perform a single measurement, i.e. does not receive any input. So far, this effect has been demonstrated under the assumption that all sources in…

Quantum Physics · Physics 2021-01-04 Ivan Šupić , Jean-Daniel Bancal , Nicolas Brunner

The geometry of quantum states provides a unifying framework for estimation processes based on quantum probes, and it allows to derive the ultimate bounds of the achievable precision. We show a relation between the statistical distance…

Quantum Physics · Physics 2016-11-28 Paolo Giorda , Michele Allegra

Measurement incompatibility underpins randomness generation in nonlocal phenomena. However, at its root, a more fundamental quantum feature is noncommuting (or coherent) measurements. This raises a central question: How can we operationally…

Quantum Physics · Physics 2026-03-09 Chellasamy Jebarathinam , Huan-Yu Ku , Hsi-Sheng Goan

Quantifying coherence is an essential endeavor for both quantum foundations and quantum technologies. In this paper, we put forward a quantitative measure of coherence by following the axiomatic definition of coherence measures introduced…

Quantum Physics · Physics 2017-07-06 C. L. Liu , Da-Jian Zhang , Xiao-Dong Yu , Qi-Ming Ding , Longjiang Liu

Any quantum resource theory is based on free states and free operations, i.e., states and operations which can be created and performed at no cost. In the resource theory of coherence free states are diagonal in some fixed basis, and free…

Quantum Physics · Physics 2017-01-06 Julio I. de Vicente , Alexander Streltsov

We characterize minimal measurement setups for validating the quantum coherence of an unknown quantum state. We show that for a $d$-level system, the optimal strategy consists of measuring $d$ orthonormal bases such that each measured basis…

Quantum Physics · Physics 2018-06-27 Claudio Carmeli , Teiko Heinosaari , Sabrina Maniscalco , Jussi Schultz , Alessandro Toigo