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We give lower and upper bounds on both the Lyapunov exponent and generalised Lyapunov exponents for the random product of positive and negative shear matrices. These types of random products arise in applications such as fluid stirring…

Dynamical Systems · Mathematics 2022-07-20 Rob Sturman , Jean-Luc Thiffeault

We study lower bounds on the Lyapunov exponent associated with one-frequency quasiperiodic Schr\"odinger operators with an added finite valued background potential. We prove that, for sufficiently large coupling constant, the Lyapunov…

Spectral Theory · Mathematics 2022-06-24 Matthew Powell

Discrimination between unknown processes chosen from a finite set is experimentally shown to be possible even in the case of non-orthogonal processes. We demonstrate unambiguous deterministic quantum process discrimination (QPD) of…

Quantum Physics · Physics 2015-05-13 Anthony Laing , Terry Rudolph , Jeremy L. O'Brien

The intuition that the precision of observables is constrained by thermodynamic costs has recently been formalized through thermodynamic and kinetic uncertainty relations. While such trade-offs have been extensively studied in Markovian…

Quantum Physics · Physics 2026-05-13 Tan Van Vu , Ryotaro Honma , Keiji Saito

Previously derived expressions for the characteristic function of work performed on a quantum system by a classical external force are generalized to arbitrary initial states of the considered system and to Hamiltonians with degenerate…

Statistical Mechanics · Physics 2008-07-11 Peter Talkner , Peter Hanggi , Manuel Morillo

A fundamental requirement for the emergence of classical behavior from an underlying quantum description is that certain observed quantum systems make a transition to chaotic dynamics as their action is increased relative to $\hbar$. While…

Quantum Physics · Physics 2017-02-01 Jason F. Ralph , Kurt Jacobs , Mark J. Everitt

Quantum phase estimation is one of the key algorithms in the field of quantum computing, but up until now, only approximate expressions have been derived for the probability of error. We revisit these derivations, and find that by ensuring…

Quantum Physics · Physics 2012-02-13 James M. Chappell , Max A. Lohe , Lorenz von Smekal , Azhar Iqbal , Derek Abbott

Quantum-proof randomness extractors are an important building block for classical and quantum cryptography as well as device independent randomness amplification and expansion. Furthermore they are also a useful tool in quantum Shannon…

Quantum Physics · Physics 2017-05-05 Mario Berta , Omar Fawzi , Volkher B. Scholz

Quantum information science currently poses a troubling contradiction. It can be summarized as: (1) To factor efficiently, quantum computers must perform exponentially precise energy estimation. (2) Exponentially precise energy estimation…

General Physics · Physics 2025-03-17 Liam P. McGuinness

The procedure commonly used in textbooks for determining the eigenvalues and eigenstates for a particle in an attractive Coulomb potential is not symmetric in the way the boundary conditions at $r=0$ and $r \rightarrow \infty$ are…

General Physics · Physics 2018-01-09 A. A. Othman , M. de Montigny , F. Marsiglio

The problem of distinguishing two unitary transformations, or quantum gates, is analyzed and a function reflecting their statistical distinguishability is found. Given two unitary operations, $U_1$ and $U_2$, it is proved that there always…

Quantum Physics · Physics 2009-11-07 A. Acin

In certain circumstances, the uncertainty, $\Delta S [\phi]$, of a quantum observable, $S$, can be bounded from below by a finite overall constant $\Delta S>0$, \emph{i.e.}, $\Delta S [\phi] \geq \Delta S$, for all physical states $\phi$.…

Quantum Physics · Physics 2015-08-25 R. T. W. Martin , A. Kempf

Mathematical core of quantum mechanics is the theory of unitary representations of symmetries of physical systems. We argue that quantum behavior is a natural result of extraction of "observable" information about systems containing…

Quantum Physics · Physics 2011-10-03 Vladimir V. Kornyak

The exponential decay law is well established since its first derivation in 1928, however it is not exact but only an approximate description. In recent years some experimental and theoretical indications for non-exponential decay have been…

Quantum Physics · Physics 2023-01-31 M. S. Hosseini-Ghalehni , B. Azadegan , S. A. Alavi

In quantum information, most information processing processes involve quantum channels. One manifestation of a quantum channel is quantum operation acting on quantum states. The coherence of quantum operations can be considered as a quantum…

Quantum Physics · Physics 2022-11-23 Xiaorong Wang , Ting Gao , Fengli Yan

We compute semi-analytic and numerical estimates for the largest Lyapunov exponent in a many-particle system with long-range interactions, extending previous results for the Hamiltonian Mean Field model with a cosine potential. Our results…

Statistical Mechanics · Physics 2020-06-24 Moisés F. P. Silva , Tarcísio M. Rocha Filho , Yves Elskens

Chernoff's bound binds a tail probability (ie. $Pr(X \ge a)$, where $a \ge EX$). Assuming that the distribution of $X$ is $Q$, the logarithm of the bound is known to be equal to the value of relative entropy (or minus Kullback-Leibler…

Probability · Mathematics 2012-08-27 M. Grendar, , M. Grendar

We consider the convex sets of QO's (quantum operations) and POVM's (positive operator valued measures) which are covariant under a general finite-dimensional unitary representation of a group. We derive necessary and sufficient conditions…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano

We consider the Schr\"odinger operator on the quantum graph whose edges connect the points of ${\Bbb Z}$. The numbers of the edges connecting two consecutive points $n$ and $n+1$ are read along the orbits of a shift of finite type. We prove…

Mathematical Physics · Physics 2025-03-18 Oleg Safronov

We present a number of arguments to demonstrate that a quantum analog of Cherenkov effect occurs when two dispersive objects are in relative motion. Specifically we show that two semi-infinite plates experience friction beyond a threshold…

Quantum Physics · Physics 2013-11-04 Mohammad F. Maghrebi , Ramin Golestanian , Mehran Kardar