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Quantum uncertainty relations impose fundamental limits on the joint knowledge that can be acquired from complementary observables: perfect knowledge of a quantum state in one basis implies maximal indetermination in all other mutually…

We give an entirely new approach to the problem of mutually unbiased bases (MUBs), based on a Fourier analytic technique in additive combinatorics. The method provides a short and elegant generalization of the fact that there are at most…

Quantum Physics · Physics 2010-09-14 Mate Matolcsi

Quantum tomography is an important tool for obtaining information about the quantum state from experimental data. In this study, we conduct a comparative analysis of various quantum tomography protocols, including protocols based on highly…

Quantum Physics · Physics 2022-01-11 Yu. I. Bogdanov , B. I. Bantysh , N. A. Bogdanova , K. B. Koksharov , V. F. Lukichev

A complete set of N+1 mutually unbiased bases (MUBs) forms a convex polytope in the N^2-1 dimensional space of NxN Hermitian matrices of unit trace. As a geometrical object such a polytope exists for all values of N, while it is unknown…

Quantum Physics · Physics 2007-05-23 Ingemar Bengtsson , Asa Ericsson

We present the marginal unbiased score expansion (MUSE) method, an algorithm for generic high-dimensional hierarchical Bayesian inference. MUSE performs approximate marginalization over arbitrary non-Gaussian latent parameter spaces,…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Marius Millea , Uros Seljak

The paper gives a short introduction to mutually unbiased bases and the Welch bounds and demonstrates that the latter is a good technical tool to explore the former. In particular, a criterion for a system of vectors to satisfy the Welch…

Quantum Physics · Physics 2008-07-22 Aleksandrs Belovs , Juris Smotrovs

One way to construct a maximal set of mutually unbiased bases (MUBs) in a prime-power dimensional Hilbert space is by means of finite phase-space methods. MUBs obtained in this way are covariant with respect to some subgroup of the group of…

Mathematical Physics · Physics 2017-05-29 Claudio Carmeli , Jussi Schultz , Alessandro Toigo

Every Maximally Entangled State (MES) of two d-dimensional particles is shown to be a product state of suitably chosen collective coordinates. The state may be viewed as defining a "point" in a "phase space" like d^2 array representing d^2…

Quantum Physics · Physics 2016-11-26 M. Revzen

The construction of multipartite unextendible product bases (UPBs) is a basic problem in quantum information. We respectively construct two families of $2\times2\times4$ and $2\times2\times2\times4$ UPBs of size eight by using the existing…

Quantum Physics · Physics 2023-01-18 Taiyu Zhang , Lin Chen

This is a review of the problem of Mutually Unbiased Bases in finite dimensional Hilbert spaces, real and complex. Also a geometric measure of "mubness" is introduced, and applied to some recent calculations in six dimensions (partly done…

Quantum Physics · Physics 2015-06-26 Ingemar Bengtsson

We present a quantum information theoretic version of the Klein-Nishina formula. This formulation singles out the quantity, the a priori visibility, that quantifies the ability to deduce the polarisation property of single photons. The…

Quantum Physics · Physics 2019-08-13 B. C. Hiesmayr , P. Moskal

In this work quantum metrology techniques are applied to the imaging of objects with a non-uniform refractive spatial profile. A sensible improvement on the classical accuracy is shown to be found when the "Twin Beam State" (TWB) is used.…

Optics · Physics 2020-09-21 Giuseppe Ortolano , Ivano Ruo Berchera , Enrico Predazzi

We initiate a systematic study of triplets of mutually unbiased bases (MUBs). We show that in $\mathbb{C}^d$ each MUB-triplet is characterized by a $d\times d\times d$ object that we call a Hadamard cube. We describe the basic properties of…

Combinatorics · Mathematics 2025-07-22 Máte Matolcsi , Ákos K. Matszangosz , Dániel Varga , Mihály Weiner

In quantum mechanics some properties are maximally incompatible, such as the position and momentum of a particle or the vertical and horizontal projections of a 2-level spin. Given any definite state of one property the other property is…

Quantum Physics · Physics 2009-11-13 A. J. Skinner , V. A. Newell , R. Sanchez

We describe a quantum state tomography scheme which is applicable to a system described in a Hilbert space of arbitrary finite dimensionality and is constructed from sequences of two measurements. The scheme consists of measuring the…

Quantum Physics · Physics 2015-06-04 Amir Kalev , Pier A. Mello

In this paper, we consider the problem of Mutually Unbiased Bases in prime dimension $d$. It is known to provide exactly $d+1$ mutually unbiased bases. We revisit this problem using a class of circulant $d \times d$ matrices. The…

Mathematical Physics · Physics 2007-10-31 M. Combescure

We use formal matrices whose entries we view as vector variables taking unit vectors values in one-qubit Hilbert spaces of a multiqubit quantum system. We construct many unextendible product bases (UPBs) of new sizes in such systems and…

Quantum Physics · Physics 2024-01-23 Lin Chen , Dragomir Z. Djokovic

In view of the tomographic-probability representation of quantum states, we reconsider the approach to quantumness tests of a single system developed in [Alicki and Van Ryn 2008 J. Phys. A: Math. Theor. 41 062001]. For qubits we introduce a…

Quantum Physics · Physics 2009-05-01 S. N. Filippov , V. I. Man'ko

We provide a construction of sets of (d/2+1) mutually unbiased bases (MUBs) in dimensions d=4,8 using maximal commuting classes of Pauli operators. We show that these incomplete sets cannot be extended further using the operators of the…

Quantum Physics · Physics 2014-02-05 Prabha Mandayam , Somshubhro Bandyopadhyay , Markus Grassl , William K. Wootters

We discuss the state tomography of a fixed qubit (a spin-1/2 target particle), which is in general in a mixed state, through 1D scattering of a probe qubit off the target. Two strategies are presented, by making use of different degrees of…

Quantum Physics · Physics 2010-01-09 Antonella De Pasquale , Kazuya Yuasa , Hiromichi Nakazato