Direct Characteristic-Function Tomography of the Quantum States of Quantum Fields

Abstract

Herein, we propose a novel strategy for implementing a direct readout of the symmetric characteristic function of the quantum states of quantum fields without the involvement of idealized measurements, an aspect that has always been deemed ill-defined in quantum field theory. This proposed scheme relies on the quantum control and measurements of an auxiliary qubit locally coupled to the quantum fields. By mapping the expectation values of both the real and imaginary parts of the field displacement operator to the qubit states, the qubit's readout provides complete information regarding the symmetric characteristic function. We characterize our technique by applying it to the Kubo-Martin-Schwinger (thermal) and squeezed states of a quantum scalar field. In addition, we have discussed general applications of this approach to analogue-gravity systems, such as Bose-Einstein condensates, within the scope of state-of-the-art experimental capabilities. This proposed strategy may serve as an essential in understanding and optimizing the control of quantum fields for relativistic quantum information applications, particularly in exploring the interplay between gravity and quantum, for example, the relation to locality, causality, and information.

9+4 pages, 3 figures

References in corpus (18)

• Single-shot read-out of an individual electron spin in a quantum dot
• Experimental Quantum State Tomography of Optical Fields and Ultrafast Statistical Sampling
• Gibbons-Hawking Effect in the Sonic de Sitter Space-Time of an Expanding Bose-Einstein-Condensed Gas
• Gaussian states in continuous variable quantum information
• Relativistic Quantum Teleportation with Superconducting Circuits
• Relativistic Quantum Information in Detectors-Field Interactions
• Directly estimating non-classicality
• Observer dependence for the phonon content of the sound field living on the effective curved space-time background of a Bose-Einstein condensate
• Processing quantum information with relativistic motion of atoms
• Relativistic Quantum Metrology in Open System Dynamics
• Quantum teleportation between moving detectors
• Continuous variable quantum state tomography of photoelectrons
• Probing Lorentz-Invariance-Violation Induced Nonthermal Unruh Effect in Quasi-Two-Dimensional Dipolar Condensates
• Does relativistic motion always degrade quantum Fisher information?
• Probing cosmic string spacetime through parameter estimation
• Pulsed Quantum-State Reconstruction of Dark Systems
• Fisher Information of a Black Hole Spacetime
• A non-perturbative analysis of spin-boson interactions using the Weyl relations

Cited by in corpus (8)

• Gaussian tripartite steering in Schwarzschild black hole
• Entanglement dynamics in $\kappa$-deformed spacetime
• Dissipation suppression for an Unruh-DeWitt battery with a reflecting boundary
• Dissipative dynamics of an open quantum battery in the BTZ spacetime
• Nonseparability of multipartite systems in dilaton black hole
• Multiqubit coherence of mixed states near event horizon
• Distinguishing pure and thermal states by Landauer's principle in open systems
• Quasinormal Mode Spectroscopy via Horizon-Brightened Quantum Optics