Concentration of Measure for Quantum States with a Fixed Expectation Value

Given some observable H on a finite-dimensional quantum system, we investigate the typical properties of random state vectors that have a fixed expectation value with respect to H . Under some conditions on the spectrum, we prove that this manifold of quantum states shows a concentration of measure...

Celý popis

Uloženo v:
Podrobná bibliografie
Vydáno v:Communications in mathematical physics Ročník 303; číslo 3; s. 785 - 824
Hlavní autoři: Müller, Markus P., Gross, David, Eisert, Jens
Médium: Journal Article
Jazyk:angličtina
Vydáno: Berlin/Heidelberg Springer-Verlag 01.05.2011
Springer
Témata:
ISSN:0010-3616, 1432-0916
On-line přístup:Získat plný text
Tagy: Přidat tag
Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!
Popis
Shrnutí:Given some observable H on a finite-dimensional quantum system, we investigate the typical properties of random state vectors that have a fixed expectation value with respect to H . Under some conditions on the spectrum, we prove that this manifold of quantum states shows a concentration of measure phenomenon: any continuous function on this set is almost everywhere close to its mean. We also give a method to estimate the corresponding expectation values analytically, and we prove a formula for the typical reduced density matrix in the case that H is a sum of local observables. We discuss the implications of our results as new proof tools in quantum information theory and to study phenomena in quantum statistical mechanics. As a by-product, we derive a method to sample the resulting distribution numerically, which generalizes the well-known Gaussian method to draw random states from the sphere.
ISSN:0010-3616
1432-0916
DOI:10.1007/s00220-011-1205-1