نتایج جستجو برای: density operator

تعداد نتایج: 500428  

2015
Georg P. Engel Leonardo Giusti Stefano Lottini Rainer Sommer

We compute the spectral density of the (Hermitian) Dirac operator in quantum chromodynamics with two light degenerate quarks near the origin. We use CLS/ALPHA lattices generated with two flavors of OðaÞ-improved Wilson fermions corresponding to pseudoscalar meson masses down to 190 MeVand with spacings in the range 0.05–0.08 fm. Thanks to the coverage of parameter space, we can extrapolate our ...

1998
M. Radici

The charge-current density and two-photon operators consistent with a single-particle semi-relativistic Hamiltonian are derived within a suitable functional derivative formalism which preserves gauge invariance. An application to electron scattering is presented and results are compared with a fully relativistic case and the non-relativistic cases corrected through fourth order in M−1.

Journal: :Physical review letters 1993
Verbaarschot Zahed

We investigate the spectral properties of a random matrix model, which in the large N limit, embodies the essentials of the QCD partition function at low energy. The exact spectral density and its pair correlation function are derived for an arbitrary number of flavors and zero topological charge. Their microscopic limit provide the master formulae for sum rules for the inverse powers of the ei...

2002
Vasily E. Tarasov

In this paper we discuss a model of quantum computer in which a state is an operator of density matrix and gates are general quantum operations, not necessarily unitary. A mixed state (operator of density matrix) of n two-level quantum systems is considered as an element of 4n-dimensional operator Hilbert space (Liouville space). It allows to use a quantum computer model with four-valued logic....

Journal: :CoRR 2017
Jeonghun Park Jeffrey G. Andrews Robert W. Heath

We characterize the rate coverage distribution for a spectrum-shared millimeter wave downlink cellular network. Each of multiple cellular operators owns separate mmWave bandwidth, but shares the spectrum amongst each other while using dynamic inter-operator base station (BS) coordination to suppress the resulting cross-operator interference. We model the BS locations of each operator as mutuall...

2001
Vasily E. Tarasov

In this paper we generalize the usual model of quantum computer to a model in which the state is an operator of density matrix and the gates are general superoperators (quantum operations), not necessarily unitary. A mixed state (operator of density matrix) of n twolevel quantum system (open or closed n-qubit system) is considered as an element of 4dimensional operator Hilbert space (Liouville ...

2005
A. J. Bracken J. G. Wood

Quantum mechanics has been formulated in phase space, with the Wigner function as the representative of the quantum density operator , and classical mechanics has been formulated in Hilbert space, with the Groenewold operator as the representative of the classical Liouville density function. Semiclassical approximations to the quantum evolution of the Wigner function have been defined, enabling...

‎In this short note‎, ‎we present some inequalities for relative operator entropy which are generalizations of some results obtained by Zou [Operator inequalities associated with Tsallis relative operator entropy‎, ‎{em Math‎. ‎Inequal‎. ‎Appl.}‎ ‎{18} (2015)‎, ‎no‎. ‎2‎, ‎401--406]‎. ‎Meanwhile‎, ‎we also show some new lower and upper bounds for relative operator entropy and Tsallis relative o...

2015
Danilo Alessio Di Stefano Paolo Arosio Adriano Piattelli Vittoria Perrotti Giovanna Iezzi

PURPOSE Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densiti...

Journal: :Journal of Machine Learning Research 2011
Bruno Pelletier Pierre Pudlo

Following Hartigan [1975], a cluster is defined as a connected component of the t-level set of the underlying density, i.e., the set of points for which the density is greater than t. A clustering algorithm which combines a density estimate with spectral clustering techniques is proposed. Our algorithm is composed of two steps. First, a nonparametric density estimate is used to extract the data...

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