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Related papers: Superposition detection and QMA with non-collapsin…

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We define and study a variant of QMA (Quantum Merlin Arthur) in which Arthur can make multiple non-collapsing measurements to Merlin's witness state, in addition to ordinary collapsing measurements. By analogy to the class PDQP defined by…

Quantum Physics · Physics 2024-11-06 Scott Aaronson , Sabee Grewal , Vishnu Iyer , Simon C. Marshall , Ronak Ramachandran

We find a modification to QMA where having one quantum proof is strictly less powerful than having two unentangled proofs, assuming EXP $\ne$ NEXP. This gives a new route to prove QMA(2) = NEXP that overcomes the primary drawback of a…

Quantum Physics · Physics 2024-10-28 Roozbeh Bassirian , Bill Fefferman , Itai Leigh , Kunal Marwaha , Pei Wu

Quantum entanglement is a fundamental property of quantum mechanics and plays a crucial role in quantum computation and information. We study entanglement via the lens of computational complexity by considering quantum generalizations of…

Quantum Physics · Physics 2024-03-01 Fernando Granha Jeronimo , Pei Wu

This paper studies multiple-proof quantum Merlin-Arthur (QMA) proof systems in the setting when the completeness-soundness gap is small. Small means that we only lower-bound the gap with an inverse-exponential function of the input length,…

Quantum Physics · Physics 2012-05-15 Attila Pereszlényi

We study a variant of QMA where quantum proofs have no relative phase (i.e. non-negative amplitudes, up to a global phase). If only completeness is modified, this class is equal to QMA [arXiv:1410.2882]; but if both completeness and…

Quantum Physics · Physics 2023-06-26 Roozbeh Bassirian , Bill Fefferman , Kunal Marwaha

With the example of a Stern-Gerlach measurement on a spin-1/2 atom, we show that a superposition of both paths may be observed compatibly with properties attributed to state collapse - for example, the singleness (or mutual exclusivity) of…

Quantum Physics · Physics 2022-01-05 Jay Lawrence

We initiate the systematic study of QMA algorithms in the setting of property testing, to which we refer as QMA proofs of proximity (QMAPs). These are quantum query algorithms that receive explicit access to a sublinear-size untrusted proof…

Quantum Physics · Physics 2022-10-17 Marcel Dall'Agnol , Tom Gur , Subhayan Roy Moulik , Justin Thaler

We study dynamics of the measurement process in quantum dot systems, where a particular state out of coherent superposition is observed. The ballistic point-contact placed near one of the dots is taken as a noninvasive detector. We…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 S. A. Gurvitz

Quantum superposition, collapse of wave function and quantum measurement problem are reexamined based on nonadiabatic dressed states and experimental observations on the quantum transitions. The physical mechanisms behind these processes…

Quantum Physics · Physics 2023-12-25 I. G. Koprinkov

The superposition principle is the cornerstone of quantum mechanics, leading to a variety of genuinely quantum effects. Whether the principle applies also to macroscopic systems or, instead, there is a progressive breakdown when moving to…

We study the power of QMA(2) with postselection and show that the power is equal to NEXP. Our method for showing this equality can be also used to prove that other classes with exponentially small completeness-soundness gap equals to the…

Quantum Physics · Physics 2018-06-27 Yusuke Kinoshita

In this work we attempt to confront the orthodox widespread claim present in the foundational literature of Quantum Mechanics (QM) according to which 'superpositions are never actually observed in the lab'. In order to do so, we begin by…

History and Philosophy of Physics · Physics 2020-07-03 Christian de Ronde

Coherent superpositions are one of the hallmarks of quantum mechanics and are vital for any quantum mechanical device to outperform the classically achievable. Generically, superpositions are verified in interference experiments, but…

Quantum Physics · Physics 2020-03-04 Benjamin Dive , Nikolaos Koukoulekidis , Stefanos Mousafeiris , Florian Mintert

We propose tests of the weak equivalence principle (WEP) using a torsion balance, in which superposition of energy eigenstates are created in a controllable way for the test masses. After general considerations on the significance of tests…

Quantum Physics · Physics 2025-12-09 Roberto Onofrio , Alexander R. H. Smith , Lorenza Viola

The quantum marginal problem asks whether a set of given density matrices are consistent, i.e., whether they can be the reduced density matrices of a global quantum state. Not many non-trivial analytic necessary (or sufficient) conditions…

Quantum Physics · Physics 2016-03-09 Jianxin Chen , Zhengfeng Ji , Nengkun Yu , Bei Zeng

The high resilience to de-coherence shown by a recently discovered Macroscopic Quantum Superposition (MQS) generated by a quantum injected optical parametric amplifier (QI-OPA) and involving a number of photons in excess of 5x10^4 motivates…

Quantum Physics · Physics 2015-05-13 Francesco De Martini , Fabio Sciarrino , Nicolo' Spagnolo

It was recently shown by Atserias, Buss and Mueller that the standard complexity-theoretic conjecture NEXP not in P / poly is consistent with the relatively strong bounded arithmetic theory V^0_2, which can prove a substantial part of…

Logic in Computer Science · Computer Science 2025-11-26 Neil Thapen

Aaronson, Bouland, Fitzsimons and Lee introduced the complexity class PDQP (which was original labeled naCQP), an alteration of BQP enhanced with the ability to obtain non-collapsing measurements, samples of quantum states without…

Quantum Physics · Physics 2025-12-23 David Miloschewsky , Supartha Podder

We study the geometric structure of the space of random measures $\mathcal{P}_p(\mathcal{P}_p(X))$, endowed with the Wasserstein on Wasserstein metric, where $(X, d)$ is a complete separable metric space. In this setting, we prove a metric…

Functional Analysis · Mathematics 2025-12-23 Alessandro Pinzi , Giuseppe Savaré

We show that long standing debates on the collapse and the role of the observer in quantum mechanics can be resolved experimentally via a nondistructive continuous monitoring of a single quantum system. An example of such a system, coupled…

Quantum Physics · Physics 2007-05-23 S. A. Gurvitz
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