Misuse of the minimal coupling to the electromagnetic field in quantum many-body systems

Skolimowski, Jan; Amaricci, A.; Fabrizio, Michele

doi:10.1103/physrevb.101.121104

Cited by 6 publications

(12 citation statements)

References 59 publications

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“…In its denominator we keep (ω) as a series in U and do not expand it into the numerator. Similar to the result for the absorbed power [31], this denominator suppresses the zero-frequency pole for finite U and turns it into a resonance at ω * , which approaches ω * = 2 √ π 1.88 (in units of t * = 1) in the noninteracting limit.…”

Section: Relation Between Internal and External Field In Linear Responsesupporting

confidence: 63%

“…Pumping with enveloped electric field pulses offers more flexibility than interaction protocols or continuous driving for the engineering of nontrivial metastable states. The denominator in ( 2) is due to an additional internal field generated in the sample by the external electric field [31] and helps to induce the prethermal state when the pump frequency is close to the resulting interaction-dependent resonance frequency.…”

Section: Introduction 1photoexcitation Of Correlated Electronsmentioning

confidence: 99%

“…According to Ref. [31], in addition to the latter the field which is created in the sample due to Maxwell's equations should also be taken into account. The total vector potential A(r, t) = A ext (r, t) + A sys (r, t) thus contains an internal part that obeys (∂ 2 t − c 2 ∇ 2 )A sys (r, t) = 4πc j sys (r, t).…”

Section: Introduction 1photoexcitation Of Correlated Electronsmentioning

confidence: 99%

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Photoinduced prethermalization phenomena in correlated metals

Alexander,

Kollar

2022

Preprint

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We study prethermalization phenomena in weakly interacting Hubbard systems after electric-field pump pulses with finite duration. We treat the Hubbard interaction U up to second order, applying the prethermalization paradigm for time-dependent interaction protocols, and the electric field strength beyond linear order. A scaling behavior with pulse duration is observed for the absorbed energy as well as individual prethermalized momentum occupation numbers, which we attribute to the leading quadratic orders in interaction and electric field. We show that a pronounced non-thermal momentum distribution can be created with pump pulses of suitable resonance frequencies, and discuss how to distinguish them from thermal states.

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Section: Relation Between Internal and External Field In Linear Responsesupporting

confidence: 63%

Section: Introduction 1photoexcitation Of Correlated Electronsmentioning

confidence: 99%

Section: Introduction 1photoexcitation Of Correlated Electronsmentioning

confidence: 99%

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Photoinduced prethermalization phenomena in correlated metals

Alexander,

Kollar

2022

Preprint

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“…In that context it is indeed well known that the Peierls substitution disregards local intra/interband processes, exactly those encoded by the connection coefficients, and that this can have effects on calculations of transport properties [66][67][68][69]. We notice that another issue with Peierls substitution and gauge invariance has been recently reported [70].…”

Section: Comparison With Peierls Substitutionmentioning

confidence: 71%

Gauge fixing for strongly correlated electrons coupled to quantum light

Dmytruk

Schiró

2021

Phys. Rev. B

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We discuss the problem of gauge fixing for strongly correlated electrons coupled to quantum light, described by projected low-energy models such as those obtained within tight-binding methods. Drawing from recent results in the field of quantum optics, we present a general approach to write down a quantum light-matter Hamiltonian in either dipole or Coulomb gauge which is explicitly connected by a unitary transformation, thus ensuring gauge equivalence even after projection. The projected dipole gauge Hamiltonian features a linear light-matter coupling and an instantaneous self-interaction for the electrons, similar to the structure in the full continuum theory. On the other hand, in the Coulomb gauge the photon field enters in a highly nonlinear way, through phase factors that dress the electronic degrees of freedom. We show that our approach generalizes the well-known Peierls approximation, to which it reduces when only local, on-site orbital contributions to lightmatter coupling are taken into account. As an application we study a two-orbital model of interacting electrons coupled to a uniform cavity mode, recently studied in the context of excitonic superradiance and associated no-go theorems. Using both gauges we recover the absence of a superradiant phase in the ground state and show that excitations on top of it, described by polariton modes, contain instead nontrivial light-matter entanglement. Our results highlight the importance of treating the nonlinear light-matter interaction of the Coulomb gauge nonperturbatively, to obtain a well-defined ultrastrong coupling limit and to not spoil gauge equivalence.

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“…In that context it is indeed well known that the Peierls substitution disregards local intra/inter-band processes, exactly those encoded by the connection coefficients, and that this can have effects on calculations of transport properties [57][58][59] . We notice that another issue with Peierls substitution and gauge invariance has been recently reported 60 .…”

Section: Comparison With Peierls Substitutionmentioning

confidence: 71%

Gauge Fixing for Strongly Correlated Electrons coupled to Quantum Light

Dmytruk,

Schiró

2020

Preprint

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We discuss the problem of gauge fixing for strongly correlated electrons coupled to quantum light, described by projected low-energy models such as those obtained within tight-binding methods. Drawing from recent results in the field of quantum optics, we present a general approach to write down quantum light-matter Hamiltonian in either dipole or Coulomb gauge which are explicitly connected by a unitary transformation, thus ensuring gauge equivalence even after projection. The projected dipole gauge Hamiltonian features a linear light-matter coupling and an instantaneous self-interaction for the electrons, similar to the structure in the full continuum theory. On the other hand, in the Coulomb gauge the photon field enters in a highly non-linear way, through phase factors that dress the electronic degrees of freedom. We show that our approach generalises the well-known Peierls approximation, to which it reduces when local, on-site orbital contributions to light-matter coupling are disregarded. As an application, we study a two-orbital model of interacting electrons coupled to a uniform cavity mode, recently studied in the context of excitonic superradiance and associated no-go theorems. Using both gauges we recover the absence of superradiant phase in the ground state and show that excitations on top of it, described by polariton modes, contain instead non-trivial light-matter entanglement. Our results highlight the importance of treating the nonlinear light-matter interaction of the Coulomb gauge non-perturbatively, to obtain a well-defined ultrastrong coupling limit and to not spoil gauge equivalence.

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Misuse of the minimal coupling to the electromagnetic field in quantum many-body systems

Cited by 6 publications

References 59 publications

Photoinduced prethermalization phenomena in correlated metals

Photoinduced prethermalization phenomena in correlated metals

Gauge fixing for strongly correlated electrons coupled to quantum light

Gauge Fixing for Strongly Correlated Electrons coupled to Quantum Light

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