Weekly Papers on Quantum Foundations (26)

R\’enyi entropy of magic. (arXiv:2106.12587v1 [quant-ph]) 上午9:37 | Lorenzo Leone, Salvatore F. E. Oliviero, Alioscia Hamma | quant-ph updates on arXiv.org We introduce a novel measure for the quantum property commonly known as $magic$ by considering the R\’enyi entropy of the probability distribution associated to a pure quantum state given by the square of the expectation value of Pauli strings… Read more →

Weekly Papers on Quantum Foundations (25)

On Causal State Updates in Quantum Field Theory. (arXiv:2106.09027v1 [quant-ph]) 上午10:21 | I. Jubb | quant-ph updates on arXiv.org In relativistic Quantum Field Theory (QFT) ideal measurements of certain observables are physically impossible without violating causality. This prompts two questions: i) can a given observable be ideally measured in QFT, and ii) if not, in what sense can it be… Read more →

Weekly Papers on Quantum Foundations (24)

Testing quantum theory with thought experiments. (arXiv:2106.05314v1 [quant-ph]) 上午9:49 | Nuriya Nurgalieva, Renato Renner | quant-ph updates on arXiv.org Quantum mechanics is one of our most successful physical theories; its predictions agree with experimental observations to an extremely high accuracy. However, the bare formalism of quantum theory does not provide straightforward answers to seemingly simple questions: for example, how should… Read more →

Weekly Papers on Quantum Foundations (23)

Testing Bell inequalities in Higgs boson decays. (arXiv:2106.01377v1 [hep-ph]) 下午5:25 | Alan Barr | quant-ph updates on arXiv.org Higgs boson decays produce pairs of W bosons in a maximally entangled state, the spins of which can be expected to violate Bell inequalities. We show that the spin density matrix of the $W^\pm$ pair may be reconstructed experimentally from the directions… Read more →

Collapse-in and Collapse-out in Partial Measurement in Quantum Mechanics and its WISE Interpretation

Gui-Lu Long (Tsinghua University) SCIENCE CHINA Physics, Mechanics & Astronomy, (2021)  https://doi.org/10.1007/s11433-021-1716-y In this short communication, we will concentrate onthe partial measurement issue and give an explanationconcerning the WISE interpretation. The essential ideaof WISE is given in Ref. [4], together with the linearcombination of unitaries (LCU) formalism of quantumcomputing. LCU has now become one of the major techniquesin quantum algorithm design…. Read more →

Weekly Papers on Quantum Foundations (22)

Faking quantum probabilites: Beyond Bell’s theorem and Tsirelson bounds. (arXiv:2105.12728v1 [quant-ph]) 上午8:50 | Marek Czachor, Kamil Nalikowski | quant-ph updates on arXiv.org Local hidden-variable model of singlet-state correlations discussed in M. Czachor, Arithmetic loophole in Bell’s Theorem: Overlooked threat to entangled-state quantum cryptography”, Acta Phys. Polon. A 139, 70-83 (2021), is shown to be a particular case of an infinite… Read more →

Weekly Papers on Quantum Foundations (21)

Quantum imprints of gravitational shockwaves. (arXiv:2105.09337v1 [hep-th]) 上午10:02 | Finnian Gray, David Kubiznak, Taillte May, Sydney Timmerman, Erickson Tjoa | quant-ph updates on arXiv.org Gravitational shockwaves are simple exact solutions of Einstein equations representing the fields of ultrarelativistic sources and idealized gravitational waves (shocks). Historically, much work has focused on shockwaves in the context of possible black hole formation in… Read more →

Weekly Papers on Quantum Foundations (20)

Blind steering in no-signalling theories. (arXiv:2007.15502v3 [quant-ph] UPDATED) 上午9:44 | Emmanuel Zambrini Cruzeiro, Nicolas Gisin, Sandu Popescu | quant-ph updates on arXiv.org Steering is usually described as a quantum phenomenon. In this article, we show that steering is not restricted to quantum theory, it is also present in more general, no-signalling theories. We present two main results: first, we show… Read more →

Weekly Papers on Quantum Foundations (19)

Page-Wootters formulation of indefinite causal order. (arXiv:2105.02304v1 [quant-ph]) 上午9:33 | Veronika Baumann, Marius Krumm, Philippe Allard Guérin, Časlav Brukner | quant-ph updates on arXiv.org One of the most fundamental open problems in physics is the unification of general relativity and quantum theory to a theory of quantum gravity. An aspect that might become relevant in such a theory is that… Read more →