Distant emitters in ultrastrong waveguide QED: Ground-state properties and non-Markovian dynamics

González-Gutiérrez, Carlos A. (Universidad de Zaragoza) ; Román-Roche, Juan ; Zueco, David

Resumen: Starting from the paradigmatic spin-boson model (SBM), we investigate the static and dynamical properties of a system of two distant two-level emitters coupled to a one-dimensional Ohmic waveguide beyond the rotating wave approximation. Employing static and dynamical polaron Ansätze we study the effects of finite separation distance on the behavior of the photon-mediated Ising-like interaction, qubit frequency renormalization, ground-state magnetization, and entanglement entropy of the two-qubit system. Based on previous works we derive an effective approximate Hamiltonian for the two-impurity SBM that preserves the excitation-number and thus facilitates the analytical treatment. In particular, it allows us to introduce non-Markovianity arising from delay-feedback effects in two distant emitters in the so-called ultrastrong coupling (USC) regime. We test our results with numerical simulations performed over a discretized circuit-QED model, finding perfect agreement with previous results, and showing interesting dynamical effects arising in ultrastrong waveguide QED with distant emitters. In particular, we revisit the Fermi two-atom problem showing that, in the USC regime, initial correlations yield two different evolutions for symmetric and antisymmetric states even before the emitters become causally connected. Finally, we demonstrate that the collective dynamics, e.g., superradiance or subradiance, are affected not only by the distance between emitters, but also by the coupling, due to significant frequency renormalization. This constitutes another dynamical consequence of the USC regime.

Idioma: Inglés

DOI: 10.1103/PhysRevA.104.053701

Año: 2021

Publicado en: Physical Review A 104, 5 (2021), 053701 [14 pp.]
ISSN: 2469-9926

Factor impacto JCR: 2.971 (2021)

Categ. JCR: PHYSICS, ATOMIC, MOLECULAR & CHEMICAL rank: 13 / 36 = 0.361 (2021) - Q2 - T2
Categ. JCR: OPTICS rank: 41 / 101 = 0.406 (2021) - Q2 - T2

Factor impacto CITESCORE: 5.7 - Physics and Astronomy (Q1)

Factor impacto SCIMAGO: 1.183 - Atomic and Molecular Physics, and Optics (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E09-17R-Q-MAD
Financiación: info:eu-repo/grantAgreement/EC/H2020/731473/EU/QuantERA ERA-NET Cofund in Quantum Technologies/QuantERA
Financiación: info:eu-repo/grantAgreement/EC/H2020/862893/EU/Molecular spin qudits offering new hope for quantum computing/FATMOLS
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2017-88358-C3-1-R
Financiación: info:eu-repo/grantAgreement/EUR/MOLSPIN-COST/CA15128

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)