# Probing the diamagnetic term in light-matter interaction

@article{Rossi2016ProbingTD,
title={Probing the diamagnetic term in light-matter interaction},
author={Matteo A. C. Rossi and Matteo Bina and Matteo G. A. Paris and Marco G. Genoni and Gerardo Adesso and Tommaso Tufarelli},
journal={arXiv: Quantum Physics},
year={2016}
}
• Published 28 April 2016
• Physics
• arXiv: Quantum Physics
We address the quantum estimation of the diamagnetic, or $A^2$, term in an effective model of light-matter interaction featuring two coupled oscillators. First, we calculate the quantum Fisher information of the diamagnetic parameter in the interacting ground state. Then, we find that typical measurements on the transverse radiation field, such as homodyne detection or photon counting, permit to estimate the diamagnetic coupling constant with near-optimal efficiency in a wide range of model…
15 Citations

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## References

SHOWING 1-10 OF 55 REFERENCES
Dicke coupling by feasible local measurements at the superradiant quantum phase transition.
• Physics
Physical review. E
• 2016
This work addresses characterization of many-body superradiant systems and establishes a fundamental connection between quantum criticality and the possibility of locally estimating the coupling constant, i.e., extracting its value by probing only a portion of the whole system, by exploiting the symplectic formalism for Gaussian states.
Light-matter decoupling and A2 term detection in superconducting circuits
• Physics
Scientific reports
• 2015
It is proved that an increase in the strength of the diamagnetic term leads to an effective decoupling of the qubit from the electromagnetic field, and that this effect is observable at any range of qubit-photon coupling.
Signatures of the A 2 term in ultrastrongly coupled oscillators
• Physics
• 2015
We study a bosonic matter excitation coupled to a single-mode cavity field via electric dipole. Counter-rotating and $A^2$ terms are included in the interaction model, ${\mathbf A}$ being the vector
Ultrastrong-coupling phenomena beyond the Dicke model
• Physics
• 2016
We study effective light-matter interactions in a circuit QED system consisting of a single $LC$ resonator, which is coupled symmetrically to multiple superconducting qubits. Starting from a minimal
Inhibition of ground-state superradiance and light-matter decoupling in circuit QED
• Physics
• 2016
We study effective light-matter interactions in a circuit QED system consisting of a single $LC$ resonator, which is coupled symmetrically to multiple superconducting qubits. Starting from a minimal
Adequacy of the Dicke model in cavity QED: A counter-no-go statement
• Physics
• 2012
The long-standing debate whether the phase transition in the Dicke model can be realized with dipoles in electromagnetic fields is yet an unsettled one. The well-known statement often referred to as
Signatures of the ultrastrong light-matter coupling regime
• Physics
• 2009
In a microcavity, light-matter coupling is quantified by the vacuum-Rabi frequency ?R. When ?R is larger than radiative and nonradiative loss rates, the system eigenstates (polaritons) are linear
Sub-cycle switch-on of ultrastrong light–matter interaction
• Physics
Nature
• 2009
This work uses a quantum-well waveguide structure to optically tune light–matter interaction from weak to ultrastrong and turn on maximum coupling within less than one cycle of light, and directly monitors how a coherent photon population converts to cavity polaritons during abrupt switching.
Superconducting qubit–oscillator circuit beyond the ultrastrong-coupling regime
• Physics
• 2017
A circuit that pairs a flux qubit with an LC oscillator via Josephson junctions pushes the coupling between light to matter to uncharted territory, with the potential for new applications in quantum
No-go theorem for superradiant quantum phase transitions in cavity QED and counter-example in circuit QED.
• Physics
Nature communications
• 2010
It is proved that if the time-independent light-matter Hamiltonian is considered, a superradiant quantum critical point is forbidden for electric dipole atomic transitions because of the oscillator strength sum rule.