Highly tunable platforms for realizing topological phases of matter are emerging from atomic and photonic systems, and offer the prospect of designing interactions between particles. The shape of the potential, besides playing an important role in the competition between different fractional quantum Hall phases, can also trigger the transition to symmetry-broken phases, or even to phases where topological and symmetry-breaking order coexist. Here, we explore the phase diagram of an interacting bosonic model in the lowest Landau level at half-filling as two-body interactions are tuned. Apart from the well-known Laughlin liquid, Wigner crystal phase, stripe, and bubble phases, we also find evidence of a phase that exhibits crystalline order at fractional filling per crystal site. The Laughlin liquid transits into this phase when pairs of bosons strongly repel each other at relative angular momentum 4ℏ. We show that such interactions can be achieved by dressing ground-state cold atoms with multiple different-parity Rydberg states.

1 aGraß, Tobias1 aBienias, Przemyslaw1 aGullans, Michael, J.1 aLundgren, Rex1 aMaciejko, Joseph1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/1809.0449302027nas a2200241 4500008004100000245007500041210006900116260001500185300001200200490000800212520128400220100001701504700002901521700002201550700002601572700002501598700002501623700002301648700001601671700002301687700002001710856005501730 2018 eng d00aObservation of three-photon bound states in a quantum nonlinear medium0 aObservation of threephoton bound states in a quantum nonlinear m c2018/02/16 a783-7860 v3593 aBound states of massive particles, such as nuclei, atoms or molecules, are ubiquitous in nature and constitute the bulk of the visible world around us. In contrast, photons typically only weakly influence each other due to their very weak interactions and vanishing mass. We report the observation of traveling three-photon bound states in a quantum nonlinear medium where the interactions between photons are mediated by atomic Rydberg states. In particular, photon correlation and conditional phase measurements reveal the distinct features associated with three-photon and two-photon bound states. Such photonic trimers and dimers can be viewed as quantum solitons with shape-preserving wavefunctions that depend on the constituent photon number. The observed bunching and strongly nonlinear optical phase are quantitatively described by an effective field theory (EFT) of Rydberg-induced photon-photon interactions, which demonstrates the presence of a substantial effective three-body force between the photons. These observations pave the way towards the realization, studies, and control of strongly interacting quantum many-body states of light.

1 aLiang, Qi-Yu1 aVenkatramani, Aditya, V.1 aCantu, Sergio, H.1 aNicholson, Travis, L.1 aGullans, Michael, J.1 aGorshkov, Alexey, V.1 aThompson, Jeff, D.1 aChin, Cheng1 aLukin, Mikhail, D.1 aVuletic, Vladan uhttp://science.sciencemag.org/content/359/6377/78302080nas a2200229 4500008004100000245007800041210006900119520136400188100002401552700001901576700002401595700001701619700002301636700002101659700001801680700002501698700001901723700002701742700001901769700002501788856003701813 2018 eng d00aPhoton propagation through dissipative Rydberg media at large input rates0 aPhoton propagation through dissipative Rydberg media at large in3 aWe study the dissipative propagation of quantized light in interacting Rydberg media under the conditions of electromagnetically induced transparency (EIT). Rydberg blockade physics in optically dense atomic media leads to strong dissipative interactions between single photons. The regime of high incoming photon flux constitutes a challenging many-body dissipative problem. We experimentally study in detail for the first time the pulse shapes and the second-order correlation function of the outgoing field and compare our data with simulations based on two novel theoretical approaches well-suited to treat this many-photon limit. At low incoming flux, we report good agreement between both theories and the experiment. For higher input flux, the intensity of the outgoing light is lower than that obtained from theoretical predictions. We explain this discrepancy using a simple phenomenological model taking into account pollutants, which are nearly-stationary Rydberg excitations coming from the reabsorption of scattered probe photons. At high incoming photon rates, the blockade physics results in unconventional shapes of measured correlation functions.

1 aBienias, Przemyslaw1 aDouglas, James1 aParis-Mandoki, Asaf1 aTitum, Paraj1 aMirgorodskiy, Ivan1 aTresp, Christoph1 aZeuthen, Emil1 aGullans, Michael, J.1 aManzoni, Marco1 aHofferberth, Sebastian1 aChang, Darrick1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/1807.0758601242nas a2200157 4500008004100000245005100041210005000092520077600142100001600918700002500934700002200959700001800981700002300999700002501022856003701047 2018 eng d00aSingle-photon bound states in atomic ensembles0 aSinglephoton bound states in atomic ensembles3 aWe illustrate the existence of single-excitation bound states for propagating photons interacting with N two-level atoms. These bound states can be calculated from an effective spin model, and their existence relies on dissipation in the system. The appearance of these bound states is in a one-to-one correspondence with zeros in the single-photon transmission and with divergent bunching in the second-order photon-photon correlation function. We also formulate a dissipative version of Levinson's theorem for this system by looking at the relation between the number of bound states and the winding number of the transmission phases. This theorem allows a direct experimental measurement of the number of bound states using the measured transmission phases.

1 aWang, Yidan1 aGullans, Michael, J.1 aBrowaeys, Antoine1 aPorto, J., V.1 aChang, Darrick, E.1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/1809.0114701499nas a2200181 4500008004100000245006100041210006000102260001500162300001100177490000800188520098100196100002001177700001801197700002501215700001901240700002101259856003701280 2017 eng d00aLight-induced fractional quantum Hall phases in graphene0 aLightinduced fractional quantum Hall phases in graphene c2017/12/15 a2474030 v1193 aWe show how to realize two-component fractional quantum Hall phases in monolayer graphene by optically driving the system. A laser is tuned into resonance between two Landau levels, giving rise to an effective tunneling between these two synthetic layers. Remarkably, because of this coupling, the interlayer interaction at non-zero relative angular momentum can become dominant, resembling a hollow-core pseudo-potential. In the weak tunneling regime, this interaction favors the formation of singlet states, as we explicitly show by numerical diagonalization, at fillings ν = 1/2 and ν = 2/3. We discuss possible candidate phases, including the Haldane-Rezayi phase, the interlayer Pfaffian phase, and a Fibonacci phase. This demonstrates that our method may pave the way towards the realization of non-Abelian phases, as well as the control of topological phase transitions, in graphene quantum Hall systems using optical fields and integrated photonic structures.

1 aGhazaryan, Areg1 aGraß, Tobias1 aGullans, Michael, J.1 aGhaemi, Pouyan1 aHafezi, Mohammad uhttps://arxiv.org/abs/1612.08748