Collective light scattering in cold atomic ensembles: super-radiance, driven Dicke model and correlations
Abstract: This talk will present our work on the observation of super-radiance in a cloud of cold atoms driven by a laser. We start from an elongated cloud of laser cooled atoms that we excite either perpendicularly or along its main axis. This situation bears some similarities with cavity quantum electrodynamics: here the cavity mode is replaced by the diffraction mode of the elongated cloud. We observe superradiant pulses of light after population inversion.
Universal dynamics of nonequilibrium quantum matter
Abstract: Today’s programmable quantum simulators offer versatile platforms for exploring many-body phases and dynamics in correlated quantum systems. In this talk, we present some new—and surprising—insights into nonequilibrium quantum dynamics inspired by such recent experimental advances. First, we focus on understanding the evolution of closed quantum systems driven through a phase transition, which is crucial for quantum state preparation and adiabatic algorithms.
Microscopic and Emergent Dynamics of Quantum Information Flows
Abstract: The past fifty years of scientific and technological progress have clearly highlighted information as a physical resource - one that can be traded for heat, work, and other energetic resources. With the ongoing new wave of quantum-based technologies, understanding the microscopic and emergent dynamics of quantum information in many-body quantum systems has thus become a priority.
Macroscopic quantum motion of a nanogram-scale object
Abstract: I will describe measurements of individual phonons in a 1 ng body of superfluid helium. When this body is in equilibrium, its phonon correlations are consistent (up to 4th order) with a thermal state of mean occupancy ~ 1. This purity is preserved even when the mode is driven to a coherent state with an amplitude corresponding to ~100,000 phonons. I will describe how these results can be used to constrain nonlinear extensions of quantum mechanics, and to distribute entanglement over kilometer-scale optical fiber networks.
Controlling light down to the single-photon level with integrated quantum photonic devices
Abstract: Light-matter interactions allow adding functionalities to photonic on-chip devices, thus enabling developments in classical and quantum light sources, energy harvesters and sensors. These advances have been facilitated by precise control in growth and fabrication techniques that have opened new pathways to the design and realization of semiconductor devices where light emission, trapping and guidance can be efficiently controlled at the nanoscale.
Rydberg atoms for molecular physics and field sensing
Abstract: Neutral atoms in highly-excited Rydberg states are actively utilized in a variety of research directions such as ultracold chemistry and many-body physics, precision measurements and emerging quantum technologies. This talk is focused on using Rydberg atoms for creating long-range molecular states and for sensing AC/DC electric fields. First, I will present a novel type of Rydberg dimer formed through long-range electric-multipole interactions between a Rydberg atom and an ion. Its vibrational spectra and stability against nonadiabatic effects will be discussed.
Disorder pinning of a composite fermion quasiparticle and FQH plateau transitions
Abstract: Composite fermion wavefunctions describe a one to one correspondence between the low energy properties of the FQH and the IQH phases which has been tested extensively in experiments and through numerical studies [1]. Here we consider the FQH state in the presence of a weak disorder potential. The full many-body problem is numerically difficult [2,3] but the effective Hamiltonian of a single quasiparticle can numerically be calculated in a weak disorder regime; and here we find a one to one correspondence between the FQH and the IQH systems [4].
Strong Coupling of Single Atoms in Optical Tweezers to a Fiber Cavity: Novel approaches to Cavity-Mediated Entanglement
Abstract: Neutral atom quantum processors can greatly benefit from integration with optical cavities. These optical interfaces can be used for fast readout for real time error detection and as a quantum networking node to entangle distant quantum processors. Here we present one candidate for such integration: a Fabry-Perot Fiber Cavity (FPFC). This system is compatible with optical tweezer arrays and enables strong coupling of multiple atoms with a single cavity mode.
Building a quantum internet with photons and electron spins
Abstract: How do we get quantum systems to ‘talk’ to each other? How can we distribute entanglement at global scales? I will describe our work tackling these challenges by using light as a robust mediator of quantum interactions between matter qubits. First, I overview the development of optically-active electron spins in silicon carbide as a platform to realize long-distance quantum links. These qubits uniquely combine world-record spin coherence, noiseless single photon emission, and nanophotonic device integration- all in a wafer-scale semiconductor.
It ain’t just a detector: A new class of optical sensors based on Optoelectronic Chromatic Dispersion in photodiodes
Abstract: Light is essential for life as we know it, and the ubiquitous PN-junction is the pervasive light sensor, whether for optical detection or for energy harvesting. Since its inception over 70 years ago, the physics behind the photodiode is now well understood, including its dependence on the illumination wavelength. However, there is a further prominent feature of photodiodes that has been largely overlooked. These devices can exhibit significant and tunable chromatic dispersion, which we call Optoelectronic Chromatic Dispersion (OED).