Rabi model beyond the rotating-wave approximation: Generation of photons from vacuum through decoherence

We show how the dynamical modulation of the qubit-field coupling strength in a circuit quantum electrodynamics architecture mimics the motion of the qubit at relativistic speeds. This allows us to propose a realistic experiment to detect microwave photons coming from simulated acceleration radiation. Moreover, by combining this technique with the dynamical Casimir physics, we enhance the toolbox for studying relativistic phenomena in quantum field theory with superconducting circuits.Circuit quantum electrodynamics (cQED) [1] has swiftly become one of the leading quantum technologies for testing fundamentals of quantum mechanics, and for the implementation of quantum information tasks. The possibility of fast tuning characteristic parameters of the interaction between superconducting qubits and the electromagnetic field allows for the experimental investigation of quantum optical systems in previously inaccessible regimes, thus enabling the exploration of a wide variety of new physical phenomena [2][3][4]. In particular, cQED is a natural arena to implement quantum field theory (QFT) concepts [5]. Indeed, the physics associated to the dynamical Casimir effect (DCE) -the generation of photons out of the quantum vacuum through the motion of boundary conditions-has been implemented in a superconducting circuit platform. This experiment opened a new avenue of research on the analysis of the role of relativistic motion in quantum information setups [6][7][8][9]. In this sense, quantum technologies are rapidly progressing from tabletop experiments to long-range networks [10] and may enter, in the near future, into the space-based realm [11]. In this scenario, relativistic effects are expected to become relevant [12].The Unruh effect [13], a paradigmatic quantum field theory prediction, consists in the excitation of ground state atoms due to their acceleration through vacuum, followed by spontaneous emission. Such a phenomenon has never been observed, requiring unachievable accelerations in order to generate detectable signals. This effect can be enhanced by many orders of magnitude when two-level quantum systems are accelerated through a single-mode high-Q cavity [14]. The relation between this cavity-enhanced acceleration radiation and the original formulation of the Unruh effect in free space has produced a thought-provoking debate [15][16][17].In this Letter, we show how the ultrafast variation of the coupling strength between a superconducting qubit and a transmission line resonator mimics the motion of the qubit at relativistic speeds. This analogy paves the way for novel experimental implementations of QFT effects associated to relativistic motion. Here, we propose the measurement of the radiation produced by an artificial atom performing simulated acceleration through a superconducting cavity. Our technique provides a novel tool for the quantum simulation of QFT in curved space times with current circuit QED technology, in addition to the observation of the DCE [4] and the possibility of generating effective sp...

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“…This results in photon growth induced by the joint effect of counterrotating terms and dissipation, as studied in Ref. [28].…”

mentioning

confidence: 92%

Relativistic motion with superconducting qubits

et al. 2015

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“…However, in the circuit quantum electrodynamic (QED), the artificial atoms may interact very strongly with on-chip resonant circuits [6][7][8][9][10], the RWA can not describe well the strong coupling regime [6]. Therefore, the JC model without the RWA is the focus of current interests [11][12][13][14][15][16][17][18][19][20][21].However, due to the inclusion of the counter-rotating terms, the Bosonic number is not conserved, the Bosonic Fock space has infinite dimensions, so any solution without the RWA is highly nontrivial. In the recent years, several non-RWA approaches have been proposed in the Dicke model [12], the quantum Zeno effect [22], and the spin-boson model [23].…”

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confidence: 99%

Exact solutions to the Jaynes-Cummings model without the rotating-wave approximation

Chen

Liu

Zhang

et al. 2011

EPL

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By using extended bosonic coherent states, the solution to the Jaynes-Cummings model without the rotating-wave approximation can be mapped to that of a polynomial equation with a single variable. The solutions to this polynomial equation can give all eigenvalues and eigenfunctions of this model with all values of the coupling strength and the detuning exactly, which can be readily applied to recent circuit quantum electrodynamic systems operating in the ultra-strong coupling regime.PACS numbers: 42.50. Pq, 03.65.Ge, 85.25.Cp, 03.67.Lx The Jaynes-Cummings (JC) model[1] describes the interaction of a two-level atom (qubit) with a single bosonic mode. It is a fundamental one in quantum optics. Based on the assumption of nearresonance and relatively weak atom-cavity coupling, the rotating-wave approximation (RWA) is usually employed, and analytically exact solution can be trivially obtained.Recently, the JC model is closely related to condensed matter physics. It can be realized in some solid-state systems recently, such as one Josephson charge qubit coupling to an electromagnetic resonator [2], the superconducting quantum interference device coupled with a nanomechanical resonator [3,4], and the most recently LC resonator magnetically coupled to a superconducting qubit [5][6][7]. In traditional quantum optics where the coupling between the two-level "natural" atom and the single bosonic mode is quite weak, RWA is the most useful approximation. However, in the circuit quantum electrodynamic (QED), the artificial atoms may interact very strongly with on-chip resonant circuits [6][7][8][9][10], the RWA can not describe well the strong coupling regime [6]. Therefore, the JC model without the RWA is the focus of current interests [11][12][13][14][15][16][17][18][19][20][21].However, due to the inclusion of the counter-rotating terms, the Bosonic number is not conserved, the Bosonic Fock space has infinite dimensions, so any solution without the RWA is highly nontrivial. In the recent years, several non-RWA approaches have been proposed in the Dicke model [12], the quantum Zeno effect [22], and the spin-boson model [23]. Especially, by using extended bosonic coherent states, the present authors have solved the Dicke model without the RWA exactly in the numerical sense [12]. The most simple N = 1 Dicke model is just the JC model. This numerically exact solutions to the JC model are also described in detail in Refs. [18,19]. To the best of our knowledge, an analytical exact solutions are still lacking in the literature to date.In this paper, we propose a new method to solve exactly the JC model without the RWA by means of extended bosonic coherent states. The correlations among bosons are added step by step until further corrections will not change the results. Different from our previous work where the pure coherent state are fixed, the eigenvalue α of the pure coherent state in this paper is tunable. By solving Schr Without the RWA, the Hamiltonian of a qubit interacting with a single bosonic mode reads ( = 1)where a ...

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“…There are many situations in which these non-resonant terms are important [74,75,76], although that is beyond the scope of this Thesis.…”

Section: Rotating Wave Approximationmentioning

confidence: 99%

Cooperative Interactions in Lattices of Atomic Dipoles

Bettles

2017

Springer Theses

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Coherent radiation by an ensemble of scatterers can dramatically modify the ensemble's optical response. This can include, for example, enhanced and suppressed decay rates (superradiance and subradiance respectively), energy level shifts, and highly directional scattering. This behaviour is referred to as cooperative, since the scatterers in the ensemble behave as a collective rather than independently. In this Thesis, we investigate the cooperative behaviour of one-and two-dimensional arrays of interacting atoms.We calculate the extinction cross-section of these arrays, analysing how the cooperative eigenmodes of the ensemble contribute to the overall extinction. Typically, the dominant eigenmode if the atoms are driven by a uniform or Gaussian light beam is the mode in which the atomic dipoles oscillate in phase together and with the same polarisation as the driving field. The eigenvalues of this mode become strongly resonant as the atom number is increased. For a one-dimensional array, the location of these resonances occurs when the atomic spacing is an integer or half integer multiple of the wavelength, thus behaving analogously to a single atom in a cavity. The interference between this mode and additional eigenmodes can result in Fano-like asymmetric lineshapes in the extinction.We find that the kagome lattice in particular exhibits an exceptionally strong interference lineshape, like a cooperative analog of electromagnetically induced transparency.Triangular, square and hexagonal lattices however are typically dominated by one single mode which, for lattice spacings of the order of a wavelength, can be highly subradiant.This can result in near-perfect extinction of a resonant driving field, signifying a significant increase in the atom-light coupling efficiency. We show that this extinction is robust to possible experimental imperfections.

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Rabi model beyond the rotating-wave approximation: Generation of photons from vacuum through decoherence

Cited by 126 publications

References 69 publications

Relativistic motion with superconducting qubits

Relativistic motion with superconducting qubits

Exact solutions to the Jaynes-Cummings model without the rotating-wave approximation

Cooperative Interactions in Lattices of Atomic Dipoles

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