New wigner function for number and phase

2011

Phys. Rev. A

We study nonclassicality in the product of the probabilities of noncommuting observables. We show that within the quantum theory, nonclassical states can provide larger probability product than classical states, so that nonclassical states approach the nonfluctuating states of the classical theory more closely than classical states. This is particularized to relevant complementary observables such as conjugate quadratures, phase and number, quadrature and number, and orthogonal angular momentum components.

Section: Classical Upperbound On the Product Of Probabilities Of mentioning

confidence: 99%

Nonclassicality in the statistics of noncommuting observables: Nonclassical states are more compatible than classical states

2011

Phys. Rev. A

“…Nevertheless, the classical/nonclassical frontier is somewhat misty [97][98][99][100][101][102][103].…”

Section: Classical Statesmentioning

confidence: 97%

Quantum-limited metrology with nonlinear detection schemes

2010

J. Photon. Energy

Quantum mechanics limit the resolution of detection schemes. Typical arrangements are based on linear processes, so that the corresponding quantum limits are usually understood as unsurpassable and ultimate. Recently it has been shown that nonlinear schemes allow signal detection and measurement with larger resolution than linear processes. In particular, this affects the quantum limits. We review the proposals introduced so far in this novel area of quantum metrology. C 2010 Society of Photo-Optical Instrumentation Engineers.

“…More specifically, for the variance, we have [16,17] (nevertheless, see Ref. [18]). In other words, they are non-negative and no more singular than a δ function.…”

Section: A Uncertainty Measuresmentioning

confidence: 99%

Contradictions between different measures of quantum uncertainty

Matía-Hernando

2012

Phys. Rev. A

We show that variance and Shannon entropy provide contradictory conclusions for the uncertainty associated with the number operator for some families of states of harmonic oscillator systems with fixed mean number, and for the uncertainty of a spin component for states with and without fixed mean. We analyze this behavior in terms of the properties of these uncertainty measures. We explore their impact on quantum metrology, examining the limits to resolution caused by number fluctuations in diverse scenarios of phase-shift detection.