Quasienergy description of the driven Jaynes-Cummings model

We study nonlinear interactions in a strongly driven optomechanical cavity, in regimes where the interactions give rise to resonant scattering between optomechanical polaritons and are thus strongly enhanced. We use a Keldysh formulation and self-consistent perturbation theory, allowing us to include self-energy diagrams at all orders in the interaction. Our main focus is understanding how nonequilibrium effects are modified by the polariton interactions, in particular the generation of nonzero effective polariton temperatures from vacuum fluctuations (both in the incident cavity drive and in the mechanical dissipation). We discuss how these effects could be observed in the output spectrum of the cavity. Our work also provides a technical toolkit that will be useful for studies of more complex optomechanical systems.

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“…This physics follows from Eqs. (39), and was discussed extensively in Ref. [17], However, as shown in Fig.…”

Section: Effective Two-phonon Absorptionmentioning

confidence: 95%

“…(39). The noise functions ^m(t) and £ nt(/) describe complex independent Gaussian noise processes with zero mean.…”

Section: Influence Of Polariton Interactions On Nonequilibrium Effmentioning

confidence: 99%

Real photons from vacuum fluctuations in optomechanics: The role of polariton interactions

Lemonde

Clerk

2015

Phys. Rev. A

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“…While in the case of Frey et al [23] the tuning of tunnel couplings was introduced by a gate, here the different tunnel couplings t z | | (or Rabi frequencies z w ) encode the MBQ state. It should be noted that the strong coupling regime also has more complex bistability behaviors [33], which should be avoided in order not to confuse the readout measurements. Unwanted multi-photon phenomena can of course complicate the readout, but they cannot, as discussed in the main text, alter the operator being projected by the measurement.…”

Section: B3 Charge Reflectometry Readoutmentioning

confidence: 99%

Majorana box qubits

et al. 2017

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Quantum information protected by the topology of the storage medium is expected to exhibit long coherence times. Another feature are topologically protected gates generated through braiding of Majorana bound states. However, braiding requires structures with branched topological segments which have inherent difficulties in the semiconductor-superconductor heterostructures now believed to host Majorana bound states. In this paper, we construct quantum bits taking advantage of the topological protection and non-local properties of Majorana bound states in a network of parallel wires, but without relying on braiding for quantum gates. The elementary unit is made from three topological wires, two wires coupled by a trivial superconductor and the third acting as an interference arm. Coulomb blockade of the combined wires spawns a fractionalized spin, non-locally addressable by quantum dots used for single-qubit readout, initialization, and manipulation. We describe how the same tools allow for measurement-based implementation of the Clifford gates, in total making the architecture universal. Proof-of-principle demonstration of topologically protected qubits using existing techniques is therefore within reach.

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“…This has profound implications on the future evolution of the system, and we will show that future qubit evolution is dependent on both the amplitude and phase of the dressed coherent state. Similar effects have previously been studied for a driven qubit-cavity system where the qubit and cavity are resonant [11,12].This manuscript is organized as follows: in section I we describe the physical system of interest and the unitary frames we will be working in; in section II we define the dressed coherent state and give analytical and numerical evidence that this is the state created after the coupled system is driven classically through the cavity degrees of freedom; in section III we discuss applications of the dressed coherent state to quantum information protocols; finally, in section IV we make concluding remarks. …”

mentioning

confidence: 54%

Entanglement generated by the dispersive interaction: The dressed coherent state

Govia

Wilhelm

2016

Phys. Rev. A

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In the dispersive regime of qubit-cavity coupling, classical cavity drive populates the cavity, but leaves the qubit state unaffected. However, the dispersive Hamiltonian is derived after both a frame transformation and an approximation. Therefore, to connect to external experimental devices, the inverse frame transformation from the dispersive frame back to the lab frame is necessary. In this work, we show that in the lab frame the system is best described by an entangled state known as the dressed coherent state, and thus even in the dispersive regime, entanglement is generated between the qubit and the cavity. Also, we show that further qubit evolution depends on both the amplitude and phase of the dressed coherent state, and use the dressed coherent state to calculate the measurement contrast of a recently developed dispersive readout protocol.The interaction between a two level system (TLS) and quantized electromagnetic radiation has been studied extensively since the beginnings of quantum mechanics, with much effort devoted to the study of physical systems described by the Jaynes-Cummings Hamiltonian [1]. Over the last few decades the fields of cavity quantum electrodynamics (CQED) and more recently circuit quantum electrodynamics (cQED) have significantly developed, allowing for the exploration of the Jaynes-Cummings interaction in a wide range of parameter regimes and physical systems. In particular in cQED, both the strong coupling regime (g κ, γ, first achieved in Rydberg atoms [2]) and the strong dispersive regime (χ κ, γ) have been reached within the last decade [3]. In cQED, a superconducting qubit serves as the TLS, while the quantized electromagnetic fields are microwaves in either a strip-line resonator or 3D microwave cavity.Contemporary experiments in cQED often work in the strong dispersive regime, where the qubit and microwave cavity are off resonance, and the Jaynes-Cummings interaction reduces to an effective second order shift in system eigen-energies. In this regime, a wide range of quantum information protocols has been demonstrated [4], including quantum teleportation [5], entanglement generation by measurement and feedback [6,7], non-classical microwave state generation [8], and error correction by stabilization measurements [9].When an empty electromagnetic cavity is driven by classical radiation, the state of the cavity is described quantum mechanically by the coherent state |α , where the complex amplitude α depends on the strength and length of the classical drive. In the dispersive regime of qubit-cavity coupling, when a classical cavity drive is applied the state of the joint system is typically described by the product state a |g |α g + b |e |α e , with no qubitcavity entanglement generated if the qubit is not initially in a superposition state.What is often overlooked is that the state a |g |α g + b |e |α e is an accurate description of the joint system * Electronic address: lcggovia@lusi.uni-sb.de state under the dispersive approximation, which involves a frame transformation ...

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Quasienergy description of the driven Jaynes-Cummings model

Cited by 32 publications

References 36 publications

Real photons from vacuum fluctuations in optomechanics: The role of polariton interactions

Real photons from vacuum fluctuations in optomechanics: The role of polariton interactions

Majorana box qubits

Entanglement generated by the dispersive interaction: The dressed coherent state

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