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We investigate the structure of quantum proof systems by establishing collapse results that reveal simplifications in their complexity landscape. By extending classical theorems such as the Karp-Lipton theorem to quantum settings and…

Quantum Physics · Physics 2025-07-08 Kartik Anand , Kabgyun Jeong , Junseo Lee

We show that nonlinear resonances in a classically mixed phase space allow to define generic, strongly entangled multi-partite quantum states. The robustness of their multipartite entanglement increases with the particle number, i.e. in the…

Quantum Physics · Physics 2009-11-13 Ignacio Garcia-Mata , Andre R. R. Carvalho , Florian Mintert , Andreas Buchleitner

We consider the minimal model program for varieties that are not Q-factorial. We show that, in many cases, its steps are simpler than expected. In particular, all flips are 1-complemented. The main applications are to log terminal…

Algebraic Geometry · Mathematics 2021-02-02 János Kollár

Quantum resources, such as entanglement, can decrease the uncertainty of a parameter-estimation procedure beyond what is classically possible. This phenomenon is well described for noiseless systems with asymptotically many measurement…

Quantum Physics · Physics 2021-08-09 Jason Saunders , Jean-Francois Van Huele

Amplitudes are the major logical object in Quantum Theory. Despite this fact they presents no physical reality and in consequence only observables can be experimetally checked. We discuss the possibility of a theory of Quantum Probabilities…

Quantum Physics · Physics 2007-05-23 J. M. A. Figueiredo

We introduce a simple sub-universal quantum computing model, which we call the Hadamard-classical circuit with one-qubit (HC1Q) model. It consists of a classical reversible circuit sandwiched by two layers of Hadamard gates, and therefore…

Quantum Physics · Physics 2018-11-19 Tomoyuki Morimae , Yuki Takeuchi , Harumichi Nishimura

By the method of intense terahertz laser spectroscopy, we provide strong evidence that if an integer quantum Hall (IQH) system has asymmetric confining potential and the external quantizing magnetic field has a nonzero in-plane component,…

Mesoscale and Nanoscale Physics · Physics 2021-06-22 Sergey A. Emelyanov

A proof of quantumness is a type of challenge-response protocol in which a classical verifier can efficiently certify the quantum advantage of an untrusted prover. That is, a quantum prover can correctly answer the verifier's challenges and…

Quantum Physics · Physics 2022-09-21 Zhenning Liu , Alexandru Gheorghiu

We present an alternative frequencists' proof of the quantum probability rule which does not make use of the frequency operator, with expectation that this can circumvent the recent criticism against the previous proofs which use it. We…

Quantum Physics · Physics 2007-10-01 Sumio Wada

Entanglement-based attacks, which are subtle and powerful, are usually believed to render quantum bit commitment insecure. We point out that the no-go argument leading to this view implicitly assumes the evidence-of-commitment to be a…

Quantum Physics · Physics 2015-06-26 R. Srikanth

A strong confluence result for Q*, a quantum lambda-calculus with measurements, is proved. More precisely, confluence is shown to hold both for finite and infinite computations. The technique used in the confluence proof is syntactical but…

Logic in Computer Science · Computer Science 2009-05-29 Ugo Dal Lago , Andrea Masini , Margherita Zorzi

On classical phase spaces admitting just one complex-differentiable structure, there is no indeterminacy in the choice of the creation operators that create quanta out of a given vacuum. In these cases the notion of a quantum is universal,…

Quantum Physics · Physics 2009-11-10 J. M. Isidro

We investigate the entanglement structure of the continuous multi-scale entanglement renormalization ansatz (cMERA) [Haegeman et al., Phys. Rev. Lett., 110, 100402 (2013)] for ground states of quantum field theories (QFTs). The cMERA,…

Quantum Physics · Physics 2018-01-17 Adrián Franco-Rubio , Guifre Vidal

We present a generalization of quantum Stein's Lemma to the situation in which the alternative hypothesis is formed by a family of states, which can moreover be non-i.i.d.. We consider sets of states which satisfy a few natural properties,…

Quantum Physics · Physics 2010-03-10 Fernando G. S. L. Brandao , Martin B. Plenio

We consider quantum metrology in noisy environments, where the effect of noise and decoherence limits the achievable gain in precision by quantum entanglement. We show that by using tools from quantum error-correction this limitation can be…

Quantum Physics · Physics 2014-03-12 W. Dür , M. Skotiniotis , F. Fröwis , B. Kraus

Since the enlightening proofs of quantum contextuality first established by Kochen and Specker, and also by Bell, various simplified proofs have been constructed to exclude the non-contextual hidden variable theory of our nature at the…

Quantum Physics · Physics 2017-12-25 Weidong Tang , Sixia Yu

We have made a variational analysis on an evolution of superconductivity from weak to strong coupling regime. In contrast to a crossover without thermodynamic anomaly found in a dilute system, we show the existence of a quantum phase…

Superconductivity · Physics 2007-05-23 S. Saito , H. Yoshimoto , Y. Y. Suzuki , S. Kurihara

We address quantum $M$-ary phase-shift keyed (PSK) communication channels in the presence of phase diffusion, and analyze the use of probabilistic noiseless linear amplifiers (NLA) to enhance performance of coherent signals. We consider…

Quantum Physics · Physics 2019-10-23 Hamza Adnane , Berihu Teklu , Matteo G. A. Paris

We construct a quantum algorithm that creates the Laughlin state for an arbitrary number of particles $n$ in the case of filling fraction one. This quantum circuit is efficient since it only uses $n(n-1)/2$ local qudit gates and its depth…

Quantum Physics · Physics 2013-05-29 J. I. Latorre , V. Picó , A. Riera

A collapse-free version of quantum theory is examined to systematically study the role of the projection postulate. This foil theory assumes "passive" measurements that do not update quantum states although measurement outcomes still occur…

Quantum Physics · Physics 2025-08-27 Vincenzo Fiorentino , Stefan Weigert