Research Scope
Cavity quantum electrodynamics (cQED) analyzes interactions between atoms or other particles and photons confined in a cavity. By placing quantum systems - including ions, molecules, quantum defects in solids, superconducting qubits, and many-body condensed matter systems - inside optically designed electromagnetic environments, RCCQ aims to exploit strong quantum light-matter coupling to manipulate quantum states, tune interactions, generate entanglement, and mitigate decoherence in open quantum systems.
RCCQ leverages the cQED to advance fundamental understanding of spin-boson coupling, many-body physics, spin squeezing, and long-range entanglement for a broad range of quantum applications including superradiant phase transition, cavity-mediated chemical reaction, hybrid quantum interconnect, quantum-limited sensing and imaging, and cavity-enabled quantum energy harvesting.
RCCQ Focus Areas
- Quantum light-matter interactions
Light-matter interactions in cQED generate dressed states when the interaction between a cavity optical mode and a quantum emitter becomes strong enough that neither the light nor the matter subsystem can be treated in isolation. The cavity-mediated coupling can be strategically leveraged to control dissipation and engineer quantum materials. The enhanced interaction between electromagnetic fields and quantum systems in the cavity can be significant even in the absence of external light due to vacuum fluctuations. Utilizing such cavity-enhanced quantum light-matter interactions, RCCQ explores pathways to modulate quantum system properties by tailoring the local electromagnetic environment in the weak (e.g., Purcell), strong, and ultrastrong coupling regimes. Meanwhile, RCCQ explores cavity-mediated interactions to couple quantum systems to generate multi-qubit gate operations and many-body entanglement.
- Cavity-mediated driven-dissipative processes
Quantum vacuum fields in cavities can alter electronic states via vacuum-matter strong coupling. In solids, giant oscillator strengths enable the ultrastrong coupling (USC) regime, where interaction energy becomes a significant fraction of bare light and matter frequencies. RCCQ explores USC in solid-state cQED systems to uncover vacuum-induced phases. RCCQ leverages Dicke cooperativity, i.e., many-body enhancement of light-matter interaction, to explore quantum-optical strategies for creating, controlling, and utilizing novel phases in condensed matter.
Beyond altering solid-state vacuum-dressed materials, USC reshapes chemical reaction landscapes. RCCQ explores reaction thermodynamics in strong to USC regimes for controllable reaction landscapes, and investigate cavity-induced nonlocal effects on electrochemical reactions and electrical conductivity. RCCQ also extends such a driven-dissipative framework to laser-cooled trapped ions via a programmable trapped-ion-coupled cavity quantum simulator to simulate complex models of open quantum systems.
- Cavity-enhanced quantum interconnect
Efficient quantum interconnects are critical for realizing distributed quantum computing and sensing for next-generation quantum technologies. By leveraging cQED to enhance light-matter coupling and mediate qubit interactions, RCCQ aims to tackle bottlenecks in remote entanglement of hybrid quantum systems including low single-photon extraction rate, optical linewidth mismatch, and inefficient microwave-optical transduction. Remote entanglement between atoms/ions and telecom spin-photon interfaces enables atomic platform integration into repeater-based quantum networks. RCCQ leverages the cQED to increase the photon extraction rate and the optical transition linewidth of atomic qubits via high-cooperativity cavities. These spin-entangled photons will travel in optical fibers to further interact with quantum memories in the quantum repeater to generate remote entanglement. Microwave-optical quantum transduction is the key enabling technology to bridge superconducting qubits with optical quantum links. RCCQ develops piezo-optomechanical cavities to realize highly efficient quantum transduction with minimal added noise.
- Quantum light for sensing and imaging
Quantum phenomena overcome classical limitations, harnessing entanglement, squeezing, and ghost imaging protocols to achieve superior sensitivity beyond classical bounds. RCCQ will utilizes cQED to improve sensing and imaging detection efficiency and resolution, and mitigate environmental decoherence. By confining photons within high-Q cavities, cQED can significantly enhance light-matter interactions, increasing photon collection efficiency by orders of magnitude, thereby addressing the efficiency issue. In addition, cQED can facilitate the generation of nonclassical states of light, such as squeezed states, entangled photons, and superradiance. Such nonclassical states can reduce noise and push the sensitivity below the standard quantum limit (SQL). RCCQ utilizes cQED and quantum entanglement to investigate and demonstrate sensitivity below SQL in both fluorescence and Raman imaging.
- Cavity-enabled quantum energy systems
Cavities can enhance light-matter interactions relevant to energy conversion, including photon-assisted chemical reactions and hot-carrier processes. RCCQ investigates how quantum material properties and electromagnetic confinement can be harnessed to control and improve light harvesting and photocatalysis. By shaping the spatial and spectral properties of the electromagnetic field, optical cavities can enable the selective enhancement of interactions between light and high-energy excited states in materials. This includes the ability to manipulate the generation, energy distribution, and decay pathways of hot carriers, such as electrons and holes, far from equilibrium, that can drive otherwise inaccessible chemical transformations. Through careful engineering of cavity resonances and field localization, RCCQ explores strategies to guide these energetic charge carriers toward desired reaction pathways, thereby increasing efficiency and selectivity in photocatalytic and energy conversion processes. These efforts bridge quantum optics and materials science to unlock new paradigms in light-driven chemistry.