Single-particle dynamics and interactions of stationary-light polaritons
Zusammenfassung der Projektergebnisse
Within this project several aspects of the single particle physics of dark state polariton (DSP) were analyzed theoretically. We examined various effects that occur due to a tight longitudinal spatial confinement of stationary light. It was shown that for spatial confinement below the absorption length stationary light has to be described by a Dirac-like equation, rather than a Schrödinger like equation, thus on one hand enabling experimental observation of relativistic phenomena such as, e.g., Zitterbewegung and Klein tunneling, but also providing limits to the confinement of stationary pulses. If one is interested in studying relativistic effects a major disadvantage of this system is that the particles obeying the relativistic dynamics are superpositions of dark and bright eigensolutions of the atom-field coupling and thus are subject to major losses. We showed that using more involved coupling schemes it is possible to create higher dimensional dark spaces and thus multi-component polaritons, termed spinor polaritons, which are fully immune to radiative decay. The spinor slow-light polaritons (SSP) were shown to obey a Dirac-like equation with effective speed of light given by the slow-light group velocity and an effective mass controllable through the two-photon detuning. The possibility to control the mass of the Dirac particles allows for a simple implementation of the onedimensional random-mass Dirac model, which, due to the off-diagonal disorder shows very interesting, anomalous localization properties. We showed that the off-diagonal disorder leads to intensity correlations with a power-law scaling with exponent 3=2. Furthermore non-adiabatic corrections and the stability of SSPs were analyzed. We showed that the first nonadiabatic correction causes the emergence of a Schrödinger like dispersion and as a consequence when nonadiabatic corrections become relevant SSPs behave as non-relativistic particles with an effective spin orbit coupling (SO). The localization properties of this two-component Schrödinger particles with spin-orbit (SO) coupling moving in a random potential was investigated. By changing external parameters a crossover from an Anderson-like localized state in the Schrödinger regime to a power-law delocalized state in the Dirac regime was observed. Finally the possibility of generating artificial gauge fields for DSPs in a rotating ensembles of atoms was proposed and analyzed. The latter opens new ways to study quantum Hall physics with ultra-slow photons.
Projektbezogene Publikationen (Auswahl)
- "Confinement Limit of Dirac particles in scalar 1D potentials". Phys. Rev. A 79, 044101 (2009)
R. G. Unanyan, J. Otterbach, M. Fleischhauer
- "Confining stationary light: Dirac dynamics and Klein tunneling". Phys. Rev. Lett. 102, 063602 (2009)
J. Otterbach, R. G. Unanyan, M. Fleischhauer
- "Effective magnetic fields for stationary light". Phys. Rev. Lett. 104, 033903 (2010)
J. Otterbach, J. Ruseckas, R. G. Unanyan, G. Juzeliunas, and M. Fleischhauer
- "Spinor Slow-Light and Dirac particles with variable mass". Phys. Rev. Lett. 105, 173603 (2010)
R. G. Unanyan, J. Otterbach, M. Fleischhauer, J. Ruseckas, V. Kudriasov, and G. Juzeliunas
- "Photonic band-gap properties for two-component slow light". Phys. Rev. A 83, 063811 (2011)
J. Ruseckas, V. Kudriasov, G. Juzeliunas, R. G. Unanyan, J. Otterbach, M. Fleischhauer
- "From Anderson to anomalous localization in cold atomic gases with e¤ ective spinorbit coupling". New J. Phys. 14 073056 (2012)
M. J. Edmonds, J. Otterbach, R. G. Unanyan, M. Fleischhauer, M. Titov, P. Öhberg
(Siehe online unter https://doi.org/10.1088/1367-2630/14/7/073056)
