This award supports research and education in theoretical condensed matter physics, quantum optics, and quantum information processing using circuit and cavity QED. The research builds upon theoretical progress during the previous grant period and is driven by recent dramatic experimental and theoretical advances in the quantum mechanics of electrical circuits and in the manipulation of nanomechanical systems via radiation pressure forces. Motivated by the recent experimental progress in 'circuit QED,' the PI will continue his productive collaboration with the Yale experimental group of Schoelkopf and Devoret to realize novel and fundamental strong-coupling quantum optics in microwave electrical circuits. The PI will develop theoretical models of the many-body physics of strongly-interacting microwave polaritons in lattices of superconducting qubits and resonators. Such lattices can be used to simulate strongly-correlated bosons as well as frustrated quantum spins.

Axions are elementary particles proposed to exist by theory which are important candidates to explain the cold dark matter which pervades the universe. In the presence of a strong magnetic field they are predicted to decay into microwave photons. Circuit QED advances are approaching the point where they could dramatically change the way axion dark matter searches are done. In light of recent experimental advances, the PI will evaluate the efficacy of different possible approaches to optimizing microwave photon detection in axion searches.

The PI will also continue collaborations on opto-nano-mechanics with the Yale experimental groups of Jack Harris and Hong Tang and begin collaboration with new faculty member Peter Rakich. A new direction with Harris will be development of models of the opto-mechanics of whispering gallery modes of deformable levitated drops of liquid helium. Another will be collaboration with Rakich on the theoretical and practical limits of narrow line widths which can be achieved in on-chip optomechanical Brillouin lasers.

Applications and extensions of quantum optics ideas for superconducting circuits and opto-mechanical systems will be developed. A new direction will be to propose and develop new ideas for quantum bath engineering which will create 'friction' with the aim to naturally relax quantum systems, not towards their ground states, but rather towards pre-determined entangled many-body states of interest. Such ideas will likely be broadly applicable beyond superconducting qubits to include atomic physics systems and other types of quantum bits and to quantum simulations.

This work has a strong interdisciplinary component which brings together ideas and methods used in the condensed matter, atomic physics, and quantum optics communities. The close collaboration of the PI with experimental groups is leading to new precision microwave measurement techniques at the single photon level which will have applications beyond quantum information processing to probing nanoscale systems generally, and is yielding new forms of ultra-low-noise microwave amplifiers and detectors.

NONTECHNICAL SUMMARY This award supports theoretical research and education on artificial atoms created from electrical circuits made from materials that are superconductors. Superconductors exhibit a quantum mechanical state which can conduct electricity without dissipation. Like real atoms, these artificial atoms can interact with a single quantum or photon of microwave radiation. These superconducting electrical circuits are being developed as the basic hardware for the construction of a quantum computer. A quantum computer would perform computations by manipulating quantum mechanical states and in principle can dramatically outperform the fastest existing computers for some problems.

In addition to this potential practical application, these superconducting circuits can be used to efficiently detect individual microwave photons. The PI will explore applications of this new capability to the improved detection of axions, elementary particles postulated to solve the 'dark matter' problem of cosmology and astrophysics.

The PI will also continue his study of the theory of opto-mechanics in which the feeble pressure exerted by light can be used to cause mechanical motion of small objects and even cool their motion. This is opening up a whole new technology with practical applications in optical communications and measurements. Of particular fundamental interest will be exploration with experimental colleagues of new ideas for applying radiation pressure of light to move and distort magnetically levitated drops of superfluid helium.

Agency
National Science Foundation (NSF)
Institute
Division of Materials Research (DMR)
Application #
1301798
Program Officer
Daryl W. Hess
Project Start
Project End
Budget Start
2013-09-15
Budget End
2016-08-31
Support Year
Fiscal Year
2013
Total Cost
$420,000
Indirect Cost
Name
Yale University
Department
Type
DUNS #
City
New Haven
State
CT
Country
United States
Zip Code
06520