Local asymptotic normality for qubit states

Details Local asymptotic normality for qubit states Local asymptotic normality for qubit states

2005-12-09

arxiv.org/abs/quant-ph/0512075v3

Phys. Rev. A, 73, 052108 (2006)

Physics

Quantum Physics

16 pages, 3 figures, published version

Scientific paper

10.1103/PhysRevA.73.052108

We consider n identically prepared qubits and study the asymptotic properties of the joint state \rho^{\otimes n}. We show that for all individual states \rho situated in a local neighborhood of size 1/\sqrt{n} of a fixed state \rho^0, the joint state converges to a displaced thermal equilibrium state of a quantum harmonic oscillator. The precise meaning of the convergence is that there exist physical transformations T_{n} (trace preserving quantum channels) which map the qubits states asymptotically close to their corresponding oscillator state, uniformly over all states in the local neighborhood. A few consequences of the main result are derived. We show that the optimal joint measurement in the Bayesian set-up is also optimal within the pointwise approach. Moreover, this measurement converges to the heterodyne measurement which is the optimal joint measurement of position and momentum for the quantum oscillator. A problem of local state discrimination is solved using local asymptotic normality.

Affiliated with

Also associated with

No associations

Rating

Local asymptotic normality for qubit states does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Local asymptotic normality for qubit states, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Local asymptotic normality for qubit states will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-372248