Colloquia & Guest Speakers
Correlated dissipation: a new resource for strong atom-photon interactions
Dr. Ana Asenjo-Garcia, Caltech
Monday, February 5, 2018
Dissipation is a pervasive problem in many areas of physics. In quantum optics, losses curb our ability to realize controlled and efficient interactions between photons and atoms, which are essential for many technologies ranging from quantum information processing to metrology. Spontaneous emission - in which photons are first absorbed by atoms and then re-scattered into undesired channels - imposes a fundamental limit in the fidelities of many quantum applications, such as quantum memories and gates. Typically, it is assumed that this process occurs at a rate given by a single isolated atom. However, this assumption can be dramatically violated: interference in photon emission and absorption generates correlations and entanglement among atoms, thus making dissipation a collective phenomenon. In this talk, I will provide a comprehensive look into the physics of subradiance, an emergent form of correlated dissipation in which interference is destructive and atomic decay is inhibited . In atomic arrays in free space, subradiant states acquire an elegant interpretation in terms of optical guided modes, which only emit due to scattering from the ends of the finite system. By interfacing atomic chains with nanophotonic structures, these states can be excited straightforwardly. Exploiting their radiative properties allows for a photon retrieval error that performs exponentially better with number of atoms than previously known bounds. This single example illustrates how correlated dissipation transcends the "standard model" of disordered atomic ensembles, and suggests that we should re-examine well-known concepts in quantum optics in a new light.
 Physical Review X 7, 031024 (2017)
Ana Asenjo Garcia is a Marie Curie Postdoctoral Fellow at Caltech. Her current interests lie at the intersection of quantum optics, atomic physics, and open quantum systems. In particular, her research focuses on how to understand and exploit correlations generated by radiative interactions between atoms. Ana received her PhD from Universidad Complutense de Madrid in 2014, under the supervision of Prof. Javier Garcia de Abajo. She then started a brief postdoc in the group of Prof. Darrick Chang at ICFO, with whom she still collaborates. These few months were the perfect launching platform for her ensuing move to Caltech in the summer of 2015, as an IQIM fellow working with Prof. Jeff Kimble. While Ana is a theoretician, she deeply enjoys the opportunity to collaborate with experimentalists.
Location: Goergen 101
Refreshments will be served.