Probability measure generated by the superfidelity

Puchała, Zbigniew; Miszczak, Jarosław Adam

doi:10.1088/1751-8113/44/40/405301

Cited by 5 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…was introduced by Uhlmann [6] and called fidelity by Jozsa [8]. Actually, the definition given by Jozsa, and used, e.g., by the authors of [10][11][12][13], is the square of F (ρ 1 , ρ 2 ), however we shall adhere to the expression (1), as most authors do. This functional has become an issue of extensive investigations [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Lower and upper bounds on the fidelity susceptibility

2012

Phys. Rev. E

View full text Add to dashboard Cite

We derive upper and lower bounds on the fidelity susceptibility in terms of macroscopic thermodynamical quantities, like susceptibilities and thermal average values.The quality of the bounds is checked by the exact expressions for a single spin in an external magnetic field. Their usefulness is illustrated by two examples of manyparticle models which are exactly solved in the thermodynamic limit: the Dicke superradiance model and the single impurity Kondo model. It is shown that as far as divergent behavior is considered, the fidelity susceptibility and the thermodynamic susceptibility are equivalent for a large class of models exhibiting critical behavior.

show abstract

Section: Introductionmentioning

confidence: 99%

Lower and upper bounds on the fidelity susceptibility

2012

Phys. Rev. E

View full text Add to dashboard Cite

show abstract

“…The exact results, which can be extracted from Refs. [16,17], are still given by (4) upon multiplication of P n ðkÞ by the correction factor C n , where…”

mentioning

confidence: 99%

MeasuringTrρnon Single Copies ofρUsing Random Measurements

2012

View full text Add to dashboard Cite

While it is known that Trρ(n) can be measured directly (i.e., without first reconstructing the density matrix) by performing joint measurements on n copies of the same state ρ, it is shown here that random measurements on single copies suffice, too. Averaging over the random measurements directly yields estimates of Trρ(n), even when it is not known what measurements were actually performed (so that ρ cannot be reconstructed).

show abstract

“…For initial states in our analysis of quantum queues we take random density matrices. The theory of random density matrices is a current subject of a much study [2,4,7]. In the case of random pure states there exists a natural probability distribution, induced by the Haar measure on the unitary group U (N ), called Fubini-Study measure.…”

Section: Initial Conditions -Random States Drawn From Hs Distributionmentioning

confidence: 99%