Revision as of 11:31, 11 February 2015

SQUIRREL

SQUIRREL (acronym for Sensing QUantum Information coRRELations) is Elena's Marie Curie research project (IEF-Fellowships for career development, FP7-PEOPLE-2013-IEF project number 623708) at the Universidad Autónoma de Madrid, starting 1 March (2014). Fabrice is the scientist in charge.

Goals

Quantum correlations are those supporting technologies such as quantum information processing. For realistic applications, one has to consider open quantum systems, that is, in contact with the classical world through lifetime and excitation.

Quantum correlations are transferred through emitted photons, electrons, etc. and characterise the quantum structure of the system and its suitability as a quantum device. The state-of-the-art is the Hanbury Brown-Twiss two-photon coincidence counting, which is a particular case of the general problem. At the speed of technological progress, it is now becoming possible to measure higher order correlations of quanta characterised in all their attributes. For instance, cross-correlating photons with fixed frequencies and arrival times is now a routine practice in many laboratories worldwide. The correct interpretation and mastering of such techniques will allow a robust implementation of quantum protocols.

Theoretically, the computation of such correlations is complicated and tedious as it needs to keep in the calculation all the degrees of freedom for each carrier. Our recently developed general formalism, "the sensing method", allows to deal for the first time with complicated quantum systems, with many degrees of freedom and particles, and to compute Nth-order correlations, with N>2, at arbitrary times and frequencies.

(See the video abstract for a quick introduction to the topic)

The goal of the SQUIRELL project is to develop and disseminate this novel and interdisciplinary theoretical approach in a wide range of quantum systems (cavity QED, superconducting circuits, atomic and semiconductor systems, plasmonic, Bose-Einstein condensates, etc.), by analysing the physics made accessible by the sensing method, by supporting experiments on quantum correlations in a variety of fields and by exploiting correlations to improve and design new quantum devices.

Context

Sensing QUantum Information coRRELations

Timeline of breakthroughs providing a background to the SQUIRREL Project.

Results and its outreach

Papers

1. Emitters of N-photon bundles, C. Sánchez-Muñoz, E. del Valle, A. González-Tudela, S. Lichtmannecker, K. Müller, M. Kaniber, C. Tejedor, J.J. Finley and F.P. Laussy. Nature Photonics 8, 550 (2014) (arXiv:1306.1578). Also see the News and Views titled Cavity quantum electrodynamics: A bundle of photons, please by Dmitry V. Strekalov.

2. Spontaneous, collective coherence in driven, dissipative cavity arrays, J. Ruiz-Rivas, E. del Valle, C. Gies, P. Gartner and M. J. Hartmann, Phys. Rev. A 90, 033808 (2014). (arXiv:1401.5776)

3. Ultrafast control of Rabi oscillations in a polariton condensate, L. Dominici, D. Colas, S. Donati, J. P. Restrepo Cuartas, M. De Giorgi, D. Ballarini, G. Guirales, J. C. López Carreño, A. Bramati, G. Gigli, E. del Valle, F. P. Laussy, D. Sanvitto. Phys. Rev. Lett. 113, 226401 (2014) (arXiv:1408.1289). Covered by mi+d and Aula Magna.

4. Violation of classical inequalities by frequency filtering, C. Sánchez Muñoz, E. del Valle, C. Tejedor, F. P. Laussy. Phys. Rev. A 90, 052111 (2014) (arXiv:1403.6182). See a summary and a related video.

5. Measuring photon correlations simultaneously in time and frequency, B. Silva, A. González Tudela, C. Sánchez Muñoz, D. Ballarini, G. Gigli, K. W. West, L. Pfeiffer, E. del Valle, D. Sanvitto, F. P. Laussy. arXiv:1406.0964

6. On-chip generation of indistinguishable photons using cavity quantum-electrodynamics, K. Müller, A. Rundquist, K. A. Fischer, T. Sarmiento, K. G. Lagoudakis, Y. A. Kelaita, C. Sánchez Muñoz, E. del Valle, F. P. Laussy, J. Vučković. arXiv:1408.5942

7. Spanning the full Poincaré sphere with polariton Rabi oscillations, D. Colas, L. Dominici, S. Donati, A.A. Pervishko, T.C.H. Liew, I.A. Shelykh, D. Ballarini, M. de Giorgi, A. Bramati, G. Gigli, E. del Valle, F.P. Laussy, A.V. Kavokin, D. Sanvitto. arXiv:1412.4758

8. Optimization of photon correlations by frequency filtering, A. Gonzalez-Tudela, E. del Valle, F. P. Laussy. arXiv:1501.01799

9. Theory of indistinguishable single photons sources with time and frequency resolution, J. C. López-Carreño and E. del Valle.

10. Photon pair generation by a driven biexciton, E. del Valle, C. Sánchez Muñoz, C. Tejedor, F. P. Laussy.

11. Quantum states of polaritons, J. C. López-Carreño, J. P. Restrepo Cuartas, E. del Valle and F. P. Laussy.

Presentations

1. St-Petersburg (Russia), 28-31 May 2014: Invited talk at the International Conference on Problems of Strongly Correlated and Interacting Systems.

2. Montpellier (France), 9-13 June 2014: Poster presentation at PLMCN14.

3. Austin (United States), 10-15 August 2014: Oral and poster presentation at ICPS.