Relation between fundamental estimation limit and stability in linear quantum systems with imperfect measurement
- Department of Engineering, Australian National University, ACT 0200 (Australia)
From the noncommutative nature of quantum mechanics, estimation of canonical observables q and p is essentially restricted in its performance by the Heisenberg uncertainty relation, <{delta}q{sup 2}><{delta}p{sup 2}>{>=}({Dirac_h}/2{pi}){sup 2}/4. This fundamental lower bound may become bigger when taking the structure and quality of a specific measurement apparatus into account. In this paper, we consider a particle subjected to a linear dynamics that is continuously monitored with efficiency {eta}(set-membership sign)(0,1]. It is then clarified that the above Heisenberg uncertainty relation is replaced by <{delta}q{sup 2}><{delta}p{sup 2}>{>=}({Dirac_h}/2{pi}){sup 2}/4{eta} if the monitored system is unstable, while there exists a stable quantum system for which the Heisenberg limit is reached.
- OSTI ID:
- 21020607
- Journal Information:
- Physical Review. A, Vol. 76, Issue 3; Other Information: DOI: 10.1103/PhysRevA.76.034102; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Prior information: How to circumvent the standard joint-measurement uncertainty relation
Yang-Mills fields on CR manifolds