000095530 001__ 95530 000095530 005__ 20220426091138.0 000095530 0247_ $$2doi$$a10.1103/PhysRevA.102.023702 000095530 0248_ $$2sideral$$a119903 000095530 037__ $$aART-2020-119903 000095530 041__ $$aeng 000095530 100__ $$0(orcid)0000-0003-2995-6615$$aRomán-Roche, J.$$uUniversidad de Zaragoza 000095530 245__ $$aBound states in ultrastrong waveguide QED 000095530 260__ $$c2020 000095530 5060_ $$aAccess copy available to the general public$$fUnrestricted 000095530 5203_ $$aWe discuss the properties of bound states in finite-bandwidth waveguide QED beyond the rotating wave approximation or excitation-number-conserving light-matter coupling models. Therefore, we extend the standard calculations to a broader range of light-matter strengths, in particular, in the so-called ultrastrong coupling regime. We do this using the polaron technique. Our main results are as follows: We compute the spontaneous emission rate, which is renormalized as compared with the Fermi golden rule formula. We generalize the existence criteria for bound states, their properties, and their role in the qubit thermalization. We discuss effective spin-spin interactions through both vacuum fluctuations and bound states. Finally, we sketch a perfect state-transfer protocol among distant emitters mediated by bound states. 000095530 536__ $$9info:eu-repo/grantAgreement/EC/H2020/742102/EU/Quantum Emitters in non-conventional baths/QUENOCOBA$$9This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 742102-QUENOCOBA$$9info:eu-repo/grantAgreement/ES/MCIU/MAT2017-88358-C3-1-R$$9info:eu-repo/grantAgreement/EUR/MOLSPIN-COST/CA15128 000095530 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000095530 590__ $$a3.14$$b2020 000095530 591__ $$aPHYSICS, ATOMIC, MOLECULAR & CHEMICAL$$b10 / 37 = 0.27$$c2020$$dQ2$$eT1 000095530 591__ $$aOPTICS$$b31 / 99 = 0.313$$c2020$$dQ2$$eT1 000095530 592__ $$a1.391$$b2020 000095530 593__ $$aAtomic and Molecular Physics, and Optics$$c2020$$dQ1 000095530 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000095530 700__ $$0(orcid)0000-0002-3230-5824$$aSánchez-Burillo, E. 000095530 700__ $$0(orcid)0000-0003-4478-1948$$aZueco, D.$$uUniversidad de Zaragoza 000095530 7102_ $$12003$$2395$$aUniversidad de Zaragoza$$bDpto. Física Materia Condensa.$$cÁrea Física Materia Condensada 000095530 773__ $$g102, 2 (2020), 023702 [17 pp.]$$pPhys. rev., A$$tPhysical Review A$$x2469-9926 000095530 8564_ $$s1375666$$uhttps://zaguan.unizar.es/record/95530/files/texto_completo.pdf$$yVersión publicada 000095530 8564_ $$s655555$$uhttps://zaguan.unizar.es/record/95530/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000095530 909CO $$ooai:zaguan.unizar.es:95530$$particulos$$pdriver 000095530 951__ $$a2022-04-26-08:55:05 000095530 980__ $$aARTICLE