scholarly journals Squeezed lasing

2020 ◽  
Author(s):  
Carlos Sánchez Muñoz ◽  
Dieter Jaksch
Keyword(s):  
Parameter Estimation ◽  
Fisher Information ◽  
Cavity Mode ◽  
Stimulated Emission ◽  
Lasing Threshold ◽  
Spectral Purity ◽  
Quantum Parameter ◽  
Squeezed Vacuum ◽  
Parametric Driving ◽  
Quantum Parameter Estimation

Abstract We introduce the idea of a squeezed laser, in which a squeezed cavity mode develops a macroscopic photonic occupation powered by stimulated emission. Above the lasing threshold, the emitted light retains both the spectral purity inherent of a laser and the photon correlations characteristic of a photonic mode with squeezed quadratures. Our proposal, which can be implemented in optical setups, relies on the parametric driving of the cavity and dissipative stabilization by a broadband squeezed vacuum. We show that the squeezed laser can find applications going beyond those of standard lasers thanks to the squeezed character, such as enhanced operation in multi-photon microscopy or Heisenberg scaling of the Fisher information in quantum parameter estimation.

scholarly journals Decoherence of quantum parameter estimation for open Dirac particle in Garfinkle–Horowitz–Strominger dilation black hole

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Yumeng Huang ◽  
Kai Yan ◽  
Yinzhong Wu ◽  
Xiang Hao
Keyword(s):  
Black Hole ◽  
Parameter Estimation ◽  
Quantum Information ◽  
Fisher Information ◽  
Quantum Channel ◽  
Quantum Fisher Information ◽  
Exclusion Principle ◽  
Quantum Parameter ◽  
Information Divergence ◽  
Quantum Parameter Estimation

AbstractWe introduce and study a quantum channel that arises from the structure of the vacuum state of Dirac fields propagating in a Garfinkle–Horowitz–Strominger ($$\mathrm {GHS}$$GHS) dilation black hole spacetime. We put forward the concept of quantum information divergence, which is a new measure for relativistic parameter estimation. We employ quantum metrology to estimate the amplitude and relative phase of a Dirac field state using the quantum Fisher information and information divergence. The decoherence of quantum parameter estimation is studied through the evolution of the Bloch vector for arbitrary initial states subjected to the quantum channel and external noises. We find that the quantum information divergence decreases more than the quantum Fisher information as a function of the radiation temperature. Due to the Pauli exclusion principle and Dirac statistics, the estimation precision will gradually decrease to a non-zero value. In order to study the decoherence in the dilation black hole, we obtain the monotonic decrease of quantum coherence when an initial field evolves from the highly correlated state to the current cosmic background. The external noises can further suppress the decoherence effect from the black hole.

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