成人大片 2015 Nobel Prize in PhysicsPhysical Review Letters (PRL) is the premier physics research journal, providing rapid publication of short reports of important fundamental research in all fields of physics. Recently, the Hughes Group has published two new PRLs, introducing exciting new ideas and discoveries in quantum optics and cavity鈥搎uantum electrodynamics (cavity-QED):
1. Floquet engineering the quantum Rabi model in the ultrastrong coupling regime
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The first PRL, , reports how the ultrastrong coupling regime of light and matter can produce real photons from vacuum (nothing!). In the realm of ultrastrong coupling (USC), unusual light-matter interactions are accessible, including virtual photon states in vacuum. However, these virtual states are not accessible and are also known to be gauge dependent (in a quantum field theory), so do not represent a physical observable. By employing a gauge-invariant time-dependent theoretical model, they show how one can Floquet engineer the quantum Rabi model (the definitive model in cavity-QED), with a periodic modulation of the cavity-dipole interaction. The authors then show how the new states can be exploited to produce real photons, addressing a long-standing problem in USC and bringing to the fore a fundamentally new regime in quantum optics.
Congratulations to Kamran Akbari, (collaborator at Riken labs, Japan) and Stephen Hughes!
2. What Is the Spectral Density of the Reservoir for a Lossy Quantized Cavity?
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The second PRL, , considers a quantum two-level system coupled to a lossy three-dimensional cavity mode, and using a rigorous quasinormal mode expansion for the photonic medium, the authors show that the frequency dependence of the quantum coupling interaction between the cavity and its photonic reservoir is not independent of the cavity contents (as is widely thought). For the single quantum emitter, they identify the correct form of the local spectral density, revealing a surprising gauge-dependent frequency scaling factor, as well as a spatially dependent correction factor. The authors thus establish the correct quantum form for the cavity-reservoir interaction, which so far has only been worked out rigorously for simple 1D geometries and show its significant impact on broadband strong coupling.
Congratulations to (collaborator at Stanford, and former student), Juanjuan Ren and Stephen Hughes!
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Cover from Optica Quantum April 2024 Edition
Cover from Optica Quantum features the research of Becca VanDrunen, Juanjuan Ren and Sebastian Franke, from the Hughes Group.