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We give an exact solution to the nonlinear optimization problem of approximating a Hermitian matrix by positive semi-definite matrices. Our algorithm was then used to judge whether a quantum state is entangled or not. We show that the exact…

Quantum Physics · Physics 2012-07-13 Xiaofen Huang , Naihuan Jing

Detecting if a graph contains a $k$-Clique is one of the most fundamental problems in computer science. The asymptotically fastest algorithm runs in time $O(n^{\omega k/3})$, where $\omega$ is the exponent of Boolean matrix multiplication.…

Data Structures and Algorithms · Computer Science 2024-08-06 Amir Abboud , Nick Fischer , Yarin Shechter

For n >= 2 a construction is given for a large family of compact convex sets K and L in n-dimensional Euclidean space such that the orthogonal projection L_u onto the subspace u^\perp contains a translate of the corresponding projection K_u…

Metric Geometry · Mathematics 2014-01-07 Christina Chen , Tanya Khovanova , Daniel A. Klain

Lattice-based cryptography has emerged as one of the most prominent candidates for post-quantum cryptography, projected to be secure against the imminent threat of large-scale fault-tolerant quantum computers. The Shortest Vector Problem…

Quantum Physics · Physics 2024-11-08 Júlia Barberà-Rodríguez , Nicolas Gama , Anand Kumar Narayanan , David Joseph

We initiate a systematic study of the time complexity of quantum divide and conquer algorithms for classical problems. We establish generic conditions under which search and minimization problems with classical divide and conquer algorithms…

Quantum Physics · Physics 2025-12-03 Jonathan Allcock , Jinge Bao , Aleksandrs Belovs , Troy Lee , Miklos Santha

This article is dedicated to cosmologies with variable speed of light (VSL) - models, which one can consider as a particular case of models of a modified gravitation. In quantum cosmology the closed universe can spontaneously nucleate out…

High Energy Physics - Theory · Physics 2011-05-17 Artyom V. Yurov , Valerian A. Yurov

We show that a topological quantum computer based on the evaluation of a Witten-Reshetikhin-Turaev TQFT invariant of knots can always be arranged so that the knot diagrams with which one computes are diagrams of hyperbolic knots. The…

Quantum Physics · Physics 2023-05-08 Eric Samperton

Quantum correlations in composite and separable quantum systems are characterized by non-vanishing quantum discord. We demonstrate the necessary and sufficient conditions for existence of hermitian witness operators for quantum discord,…

Quantum Physics · Physics 2013-01-01 S. Adhikari , A. S. Majumdar , I. Chakraborty

We derive some Quantum Central Limit Theorems for expectation values of macroscopically coarse-grained observables, which are functions of coarse-grained hermitean operators. Thanks to the hermicity constraints, we obtain positive-definite…

Quantum Physics · Physics 2023-12-06 Tien D. Kieu

Network motif identification problem aims to find topological patterns in biological networks. Identifying non-overlapping motifs is a computationally challenging problem using classical computers. Quantum computers enable solving high…

Quantum Physics · Physics 2023-11-08 Hoang M. Ngo , Tamim Khatib , My T. Thai , Tamer Kahveci

We introduce a new morphism between algebraic and hermitian K-theory. The topological analog is the Adams operation in real K-theory. From this morphism, we deduce a lower bound for the higher algebraic K-theory of a ring A in terms of the…

K-Theory and Homology · Mathematics 2016-09-07 Max Karoubi

A classical open problem in combinatorial geometry is to obtain tight asymptotic bounds on the maximum number of k-level vertices in an arrangement of n hyperplanes in d dimensions (vertices with exactly k of the hyperplanes passing below…

Computational Geometry · Computer Science 2020-03-17 M. Sharir , C. Ziv

Consider a pair of symplectic varieties dual with respect to 3D-mirror symmetry. The K-theoretic limit of the elliptic duality interface is an equivariant K-theory class of the product. We show that this class provides correspondences in…

Algebraic Geometry · Mathematics 2020-08-17 Yakov Kononov , Andrey Smirnov

Evaluating the expectation of a quantum circuit is a classically difficult problem known as the quantum mean value problem (QMV). It is used to optimize the quantum approximate optimization algorithm and other variational quantum…

Quantum Physics · Physics 2022-05-25 David Joseph , Antonio J. Martinez , Cong Ling , Florian Mintert

The general problem of finding the ground state energy of lattice Hamiltonians is known to be very hard, even for a quantum computer. We show here that this is the case even for translationally invariant systems. We also show that a quantum…

Quantum Physics · Physics 2009-11-13 K. G. H. Vollbrecht , J. I. Cirac

We exploit the connection between quantum dot Dirac operators and $\overline\partial$-Robin Laplacians. First, we find a graphical relation between their smallest positive eigenvalues, which allows us to deduce a recipe for translating…

Analysis of PDEs · Mathematics 2026-05-29 Joaquim Duran

We consider the phenomenon of quantum mechanical contextuality, and specifically parity-based proofs thereof. Mermin's square and star are representative examples. Part of the information invoked in such contextuality proofs is the…

Quantum Physics · Physics 2020-01-08 Cihan Okay , Robert Raussendorf

One says that a pair (P,Q) of ordinary differential operators specify a quantum curve if [P,Q]=const. If a pair of difference operators (K,L) obey the relation KL=const LK we say that they specify a discrete quantum curve. This terminology…

Mathematical Physics · Physics 2015-06-11 Albert Schwarz

There has been great interest in developing a theory of "Khintchine types" for manifolds embedded in Euclidean space, and considerable progress has been made for curved manifolds. We treat the case of translates of coordinate hyperplanes,…

Number Theory · Mathematics 2017-08-16 Felipe A. Ramírez

We describe a simple formalism for generating classes of quantum circuits that are classically efficiently simulatable and show that the efficient simulation of Clifford circuits (Gottesman-Knill theorem) and of matchgate circuits…

Quantum Physics · Physics 2008-12-25 Richard Jozsa