English
Related papers

Related papers: Comparison of unitary transforms

200 papers

The test of modifications to quantum mechanics aimed at identifying the fundamental reasons behind the un-observability of quantum mechanical superpositions at the macro-scale is a crucial goal of modern quantum mechanics. Within the…

Quantum Physics · Physics 2014-06-03 M. Bahrami , M. Paternostro , A. Bassi , H. Ulbricht

This paper deals with the comparison of several stationary processes with unequal sample sizes. We provide a detailed theoretical framework on the testing problem for equality of spectral densities in the bivariate case, after which the…

Statistics Theory · Mathematics 2012-07-25 Philip Preuß , Thimo Hildebrandt

Quantum state tomography, the ability to deduce the state of a quantum system from measured data, is the gold standard for verification and benchmarking of quantum devices. It has been realized in systems with few components, but for larger…

Local unitary equivalence is an important ingredient for quantifying and classifying entanglement. Verifying whether or not two quantum states are local unitary equivalent is a crucial problem, where only the case of multipartite pure…

Quantum Physics · Physics 2024-02-27 Qing Zhou , Yi-Zheng Zhen , Xin-Yu Xu , Shuai Zhao , Wen-Li Yang , Shao-Ming Fei , Li Li , Nai-Le Liu , Kai Chen

We describe an efficient way for measuring the concurrence of the hyperentanglement. In this protocol, the hyperentangled state is encoded in both polarization and momentum degrees of freedom. We show that the concurrences of both…

Quantum Physics · Physics 2014-01-10 Yu-Bo Sheng , Lan Zhou

We review two general criteria for deciding whether a pure bipartite quantum state describing a system of two identical particles is entangled or not. The first one considers the possibility of attributing a complete set of objective…

Quantum Physics · Physics 2009-11-11 GianCarlo Ghirardi , Luca Marinatto

We perform a systematic comparison of various numerical schemes for the approximation of interface problems. We consider unfitted approaches in view of their application to possibly moving configurations. Particular attention is paid to the…

Numerical Analysis · Mathematics 2023-04-25 Daniele Boffi , Andrea Cangiani , Marco Feder , Lucia Gastaldi , Luca Heltai

A policy maker faces a sequence of unknown outcomes. At each stage two (self-proclaimed) experts provide probabilistic forecasts on the outcome in the next stage. A comparison test is a protocol for the policy maker to (eventually) decide…

Methodology · Statistics 2019-09-19 Itay Kavaler , Rann Smorodinsky

In a typical Internet-of-Things setting that involves scientific applications, a target computation can be evaluated in many different ways depending on the split of computations among various devices. On the one hand, different…

Performance · Computer Science 2022-08-09 Aravind Sankaran , Paolo Bientinesi

Symmetric quantum states are fascinating objects. They correspond to multipartite systems that remain invariant under particle permutations. This symmetry is reflected in their compact mathematical characterisation but also in their unique…

Quantum Physics · Physics 2025-07-15 Carlo Marconi , Guillem Müller-Rigat , Jordi Romero-Pallejà , Jordi Tura , Anna Sanpera

Ensembling is a simple and popular technique for boosting evaluation performance by training multiple models (e.g., with different initializations) and aggregating their predictions. This approach is commonly reserved for the largest…

Machine Learning · Computer Science 2020-05-05 Dan Kondratyuk , Mingxing Tan , Matthew Brown , Boqing Gong

We introduce a task that we call partial decoupling, in which a bipartite quantum state is transformed by a unitary operation on one of the two subsystems and then is subject to the action of a quantum channel. We assume that the subsystem…

Quantum Physics · Physics 2021-10-20 Eyuri Wakakuwa , Yoshifumi Nakata

There is a useful counterpart of conformal prediction for e-values, called conformal e-prediction. Conformal prediction can serve as basis for testing the assumption of exchangeability, leading to conformal testing. Similarly, conformal…

Statistics Theory · Mathematics 2024-11-05 Vladimir Vovk , Ilia Nouretdinov , Alex Gammerman

Quantum-enhanced metrology can be achieved by entangling a probe with an auxiliary system, passing the probe through an interferometer, and subsequently making measurements on both the probe and auxiliary system. Conceptually, this…

Quantum Physics · Physics 2015-09-22 Simon A. Haine , Stuart S. Szigeti

A convergent iterative procedure is proposed for the calculation of the relative entropy of entanglement of a given bipartite quantum state. When this state turns out to be non-separable the algorithm provides the corresponding optimal…

Quantum Physics · Physics 2009-11-07 Jaroslav Rehacek , Zdenek Hradil

Particle filters provide Monte Carlo approximations of intractable quantities such as point-wise evaluations of the likelihood in state space models. In many scenarios, the interest lies in the comparison of these quantities as some…

Methodology · Statistics 2016-07-19 Pierre E. Jacob , Fredrik Lindsten , Thomas B. Schön

There is a natural equivalence relation on representations of the states of a given quantum system in a Hilbert space, two representations being equivalent iff they are related by a unitary transformation. There are two equivalence classes,…

Quantum Physics · Physics 2007-05-23 Robert A. Van Wesep

We present a criterion, based on three commutator relations, that allows to decide whether two self-adjoint matrices with non-overlapping support are simultaneously unitarily similar to quasidiagonal matrices, i.e., whether they can be…

Quantum Physics · Physics 2007-08-22 M. Kleinmann , H. Kampermann , Ph. Raynal , D. Bruss

The equivalence of multipartite quantum mixed states under local unitary transformations is studied. A criterion for the equivalence of non-degenerate mixed multipartite quantum states under local unitary transformations is presented.

Quantum Physics · Physics 2015-06-26 X. H. Gao , S. Alberverio , S. M. Fei , Z. X. Wang

Statistical matching is an effective method for estimating causal effects in which treated units are paired with control units with ``similar'' values of confounding covariates prior to performing estimation. In this way, matching helps…

Methodology · Statistics 2023-09-13 Sanjeewani Weerasingha , Michael J. Higgins