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Any two-qubit state can be faithfully represented by a steering ellipsoid inside the Bloch sphere, but not every ellipsoid inside the Bloch sphere corresponds to a two-qubit state. We give necessary and sufficient conditions for when the…

Quantum Physics · Physics 2015-03-23 Antony Milne , Sania Jevtic , David Jennings , Howard Wiseman , Terry Rudolph

We show that under certain circumstances an atom can follow an oscillatory motion in a periodic laser profile with a Gaussian envelope. These oscillations can be well explained by using a model of energetically forbidden spatial regions.…

Quantum Physics · Physics 2009-10-31 Luis Santos , Luis Roso

The maximum clique problem (MCP) is to find the largest complete subgraph in an undirected graph, that is, the subgraph in which there are edges between every two different vertices. It is an NP-Hard problem with wide applications,…

Quantum Physics · Physics 2025-09-03 Wenmin Han , Shiqi Zheng , Peian Chen , Yukun Wang

In contrast to a "single particle table-top trap", an essential feature of a storage ring "trap" is that $10^{10}$ or more particles can have their spins aligned in a polarized beam. This is a nunber of polarized particles large enough for…

Accelerator Physics · Physics 2021-09-22 Richard M Talman

We present a novel method to study the Bloch space of the qutrit system by examining the Bloch trajectories in it. Since such system is inherently a three-level quantum system, therefore we use the SU(3) group as the basis group to obtain…

Quantum Physics · Physics 2024-11-26 Surajit Sen , Tushar Kanti Dey

Physics-informed neural networks (PINNs) are a promising approach for solving partial differential equations (PDEs). Their training, however, is often difficult because multiple loss terms induced by PDE residuals and boundary or initial…

Machine Learning · Computer Science 2026-05-12 Hoyeol Yoon , Seoungbin Bae , Nam Ho-Nguyen , Dabeen Lee

Reliable communication over the discrete-input/continuous-output noncoherent multiple-input multiple-output (MIMO) Rayleigh block fading channel is considered when the signal-to-noise ratio (SNR) per degree of freedom is low. Two key…

Information Theory · Computer Science 2008-09-22 Shivratna Giri Srinivasan , Mahesh K. Varanasi

We extend a primal-dual fixed point algorithm (PDFP) proposed in [5] to solve two kinds of separable multi-block minimization problems, arising in signal processing and imaging science. This work shows the flexibility of applying PDFP…

Optimization and Control · Mathematics 2016-02-02 Peijun Chen , Jianguo Huang , Xiaoqun Zhang

We investigate dimensional constraints arising from representation theory when abstract graph edges possess internal degrees of freedom but lack geometric properties. We prove that such internal degrees of freedom can only encode…

Mathematical Physics · Physics 2026-01-21 João P. da Cruz

We analyze a quantum computer (QC) design based on nuclear spin qubits in a quasi-one-dimensional (1D) chain of non-Kramers doublet atoms. We explore the use of spatial symmetry breaking to obtain control over the local dynamics of a qubit.…

Other Condensed Matter · Physics 2009-11-10 E. Novais , A. H. Castro Neto

We find a Polyakov-type action for strings moving in a torsional Newton-Cartan geometry. This is obtained by starting with the relativistic Polyakov action and fixing the momentum of the string along a non-compact null isometry. For a flat…

High Energy Physics - Theory · Physics 2019-01-04 Troels Harmark , Jelle Hartong , Lorenzo Menculini , Niels A. Obers , Ziqi Yan

In the first part of this paper, we survey results that are associated with three types of Laplacian matrices:difference, normalized, and signless. We derive eigenvalue and eigenvector formulaes for paths and cycles using circulant matrices…

Combinatorics · Mathematics 2012-11-06 K. K. K. R. Perera , Yoshihiro Mizoguchi

A major challenge in single particle reconstruction from cryo-electron microscopy is to establish a reliable ab-initio three-dimensional model using two-dimensional projection images with unknown orientations. Common-lines based methods…

Machine Learning · Computer Science 2013-04-11 Lanhui Wang , Amit Singer , Zaiwen Wen

As an extension of two-level quantum bits (qubits), multilevel systems, so-called qudits, where d represents the Hilbert space dimension, have been predicted to reduce the number of iterations in quantum computation algorithms. This has…

We prove that for all integers $2\leq m\leq d-1$, there exists doubling measures on $\mathbb{R}^d$ with full support that are $m$-rectifiable and purely $(m-1)$-unrectifiable in the sense of Federer (i.e. without assuming…

Metric Geometry · Mathematics 2025-05-09 Matthew Badger , Raanan Schul

We show that a wide range of spin clusters with antiferromagnetic intracluster exchange interaction allows one to define a qubit. For these spin cluster qubits, initialization, quantum gate operation, and readout are possible using the same…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Florian Meier , Jeremy Levy , Daniel Loss

We study the computational content of the Brouwer Fixed Point Theorem in the Weihrauch lattice. Connected choice is the operation that finds a point in a non-empty connected closed set given by negative information. One of our main results…

Logic · Mathematics 2021-02-24 Vasco Brattka , Stéphane Le Roux , Joseph S. Miller , Arno Pauly

We use a superspin Hamiltonian defined on an infinite-dimensional Fock space with positive definite scalar product to study localization and delocalization of noninteracting spinless quasiparticles in quasi-one-dimensional quantum wires…

Disordered Systems and Neural Networks · Physics 2009-10-02 Andreas P. Schnyder , Christopher Mudry , Ilya A. Gruzberg

An internal polarized hydrogen storage cell gas target is proposed for the AD--ring to determine for the first time the two total spin--dependent cross sections $\sigma_1$ and $\sigma_2$ at antiproton beam energies in the range from 50 to…

Nuclear Experiment · Physics 2007-05-23 Paolo Lenisa , Frank Rathmann

Orbital entropies, pair entropies, and mutual information have become popular tools for analysis of strongly correlated wave functions. They can quantitatively measure how strongly an orbital participates in the electron correlation and…

Chemical Physics · Physics 2026-05-26 Jiri Pittner