Quantum sensing of open systems: Estimation of damping constants and temperature

Abstract

We determine quantum precision limits for estimation of damping constants and temperature of lossy bosonic channels. A direct application would be the use of light for estimation of the absorption and the temperature of a transparent slab. Analytic lower bounds are obtained for the uncertainty in the estimation, through a purification procedure that replaces the master equation description by a unitary evolution involving the system and ad hoc environments. For zero temperature, Fock states are shown to lead to the minimal uncertainty in the estimation of damping, with boson-counting being the best measurement procedure. In both damping and temperature estimates, sequential prethermalization measurements, through a stream of single bosons, may lead to huge gain in precision.

Gaussian quantum metrology in a dissipative environment

“…( 11) that F +,BMA κ (∞) = 0, which indicates that the metrology error becomes divergent and the corresponding metrology scheme completely breaks down in the long-encoding time regime. A similar result is also reported in many previous works [16][17][18][19][20][21][22][23][24]. It is understandable based on the fact that the information of κ in ρ(t) under the Born-Markovian approximation unidirectionally flows from the probe to the environment such that no message can be extracted in the long-encoding-time regime.…”

“…Such amazing result is caused by the anomalous equilibrium state induced by the bound state: the message of κ is partially preserved in the steady state ρ(∞) and can be persistently enlarged by prolonging the encoding time. Therefore, we can completely overcome the error-divergency problem appearing in many previous studies [16][17][18][19][20][21][22][23][24] with the help of the bound state mechanism. Moreover, one can find from Eq.…”

“…It results in the deterioration of the performance of quantum metrology. It was found that the metrology error generally becomes divergent in the longencoding-time regime under the influence of decoherence caused by environments [16][17][18][19][20][21][22][23][24]. Such phenomenon is called no-go theorem of noisy quantum metrology [21,25] and is the main bottleneck for achieving a high-precision quantum metrology in practice.…”

Quantum Fisher Information Bounds on Precision Limits of Circular Dichroism

“…Based on this formulation, we could estimate the sensitivities of chiral parameters in a standard ellipsometric setup for various input states of light. Following the QFI formalism, the sensitivity bounds for absorption rate of a single mode of the field have been evaluated with both a Gaussian state [41,42] and non-Gaussian states such as a Fock (photon number) state [43,44]. The Fock state has turned out to be an optimal choice for the estimation.…”

Quantum Fisher Information Perspective on Sensing in Anti-PT Symmetric Systems

“…The concept of Fisher information was conceived as a tool to quantify the amount of information encoded in an observable quantity about an unknown variable through statistical modeling. With the statistical properties of a quantum system described by its density matrix, the notion was subsequently generalized to the quantum formalism [29][30][31][32][33][34][35][36][37][38], and has been applied for diverse practical ends, such as for quantum metrology in lossy open systems [39][40][41][42]. In this work, we report the exact precision bound to parameter estimation in anti-PT symmetric systems and thereby, provide an overarching statistical framework for the sensing of weak perturbative effects.…”