Rydberg blockade physics in optically dense atomic media under the conditions of electromagnetically induced transparency (EIT) leads to strong dissipative interactions between single photons. We introduce a new approach to analyzing this challenging many-body problem in the limit of large optical depth per blockade radius. In our approach, we separate the single-polariton EIT physics from Rydberg-Rydberg interactions in a serialized manner while using a hard-sphere model for the latter, thus capturing the dualistic particle-wave nature of light as it manifests itself in dissipative Rydberg-EIT media. Using this approach, we analyze the saturation behavior of the transmission through one-dimensional Rydberg-EIT media in the regime of non-perturbative dissipative interactions relevant to current experiments. Our model is in good agreement with experimental data. We also analyze a scheme for generating regular trains of single photons from continuous-wave input and derive its scaling behavior in the presence of imperfect single-photon EIT.

1 aZeuthen, Emil1 aGullans, Michael1 aMaghrebi, Mohammad, F.1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/1608.0606801555nas a2200181 4500008004100000245007900041210006900120260001500189300001100204490000700215520101200222100002101234700002201255700001901277700001901296700002101315856003701336 2017 eng d00aHigh-Order Multipole Radiation from Quantum Hall States in Dirac Materials0 aHighOrder Multipole Radiation from Quantum Hall States in Dirac c2017/06/30 a2354390 v953 aTopological states can exhibit electronic coherence on macroscopic length scales. When the coherence length exceeds the wavelength of light, one can expect new phenomena to occur in the optical response of these states. We theoretically characterize this limit for integer quantum Hall states in two-dimensional Dirac materials. We find that the radiation from the bulk is dominated by dipole emission, whose spectral properties vary with the local disorder potential. On the other hand, the radiation from the edge is characterized by large multipole moments in the far-field associated with the efficient transfer of angular momentum from the electrons into the scattered light. These results demonstrate that high-order multipole transitions are a necessary component for the optical spectroscopy and control of quantum Hall and related topological states in electronic systems.

1 aGullans, Michael1 aTaylor, Jacob, M.1 aImamoglu, Atac1 aGhaemi, Pouyan1 aHafezi, Mohammad uhttps://arxiv.org/abs/1701.0346401583nas a2200181 4500008004100000245005200041210005200093260001500145300001100160490000700171520107600178100002301254700002101277700002201298700002001320700002401340856003701364 2017 eng d00aValley Blockade in a Silicon Double Quantum Dot0 aValley Blockade in a Silicon Double Quantum Dot c2017/11/13 a2053020 v963 aElectrical transport in double quantum dots (DQDs) illuminates many interesting features of the dots' carrier states. Recent advances in silicon quantum information technologies have renewed interest in the valley states of electrons confined in silicon. Here we show measurements of DC transport through a mesa-etched silicon double quantum dot. Comparing bias triangles (i.e., regions of allowed current in DQDs) at positive and negative bias voltages we find a systematic asymmetry in the size of the bias triangles at the two bias polarities. Asymmetries of this nature are associated with blocking of tunneling events due to the occupation of a metastable state. Several features of our data lead us to conclude that the states involved are not simple spin states. Rather, we develop a model based on selective filling of valley states in the DQD that is consistent with all of the qualitative features of our data.

1 aPerron, Justin, K.1 aGullans, Michael1 aTaylor, Jacob, M.1 aStewart, M., D.1 aZimmerman, Neil, M. uhttps://arxiv.org/abs/1607.0610701662nas a2200217 4500008004100000245004300041210004300084260001500127300001100142490000600153520108300159100001601242700001501258700001601273700001901289700001101308700002101319700001901340700001801359856006701377 2016 eng d00aDouble Quantum Dot Floquet Gain Medium0 aDouble Quantum Dot Floquet Gain Medium c2016/11/07 a0410270 v63 aStrongly driving a two-level quantum system with light leads to a ladder of Floquet states separated by the photon energy. Nanoscale quantum devices allow the interplay of confined electrons, phonons, and photons to be studied under strong driving conditions. Here we show that a single electron in a periodically driven DQD functions as a "Floquet gain medium," where population imbalances in the DQD Floquet quasi-energy levels lead to an intricate pattern of gain and loss features in the cavity response. We further measure a large intra-cavity photon number n_c in the absence of a cavity drive field, due to equilibration in the Floquet picture. Our device operates in the absence of a dc current -- one and the same electron is repeatedly driven to the excited state to generate population inversion. These results pave the way to future studies of non-classical light and thermalization of driven quantum systems.

1 aStehlik, J.1 aLiu, Y.-Y.1 aEichler, C.1 aHartke, T., R.1 aMi, X.1 aGullans, Michael1 aTaylor, J., M.1 aPetta, J., R. uhttp://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.04102701280nas a2200205 4500008004100000245005000041210005000091260001500141300001100156490000800167520073000175100002100905700002100926700001300947700001900960700001600979700001800995700002501013856003601038 2016 eng d00aEffective Field Theory for Rydberg Polaritons0 aEffective Field Theory for Rydberg Polaritons c2016/09/09 a1136010 v1173 aWe study non-perturbative effects in N-body scattering of Rydberg polaritons using effective field theory (EFT). We develop an EFT in one dimension and show how a suitably long medium can be used to prepare shallow N-body bound states. We then derive the effective N-body interaction potential for Rydberg polaritons and the associated N-body contact force that arises in the EFT. We use the contact force to find the leading order corrections to the binding energy of the N-body bound states and determine the photon number at which the EFT description breaks down. We find good agreement throughout between the predictions of EFT and numerical simulations of the exact two and three photon wavefunction transmission.

1 aGullans, Michael1 aThompson, J., D.1 aWang, Y.1 aLiang, Q., -Y.1 aVuletic, V.1 aLukin, M., D.1 aGorshkov, Alexey, V. uhttp://arxiv.org/abs/1605.0565101372nas a2200181 4500008004100000245007800041210006900119260001500188300001100203490000800214520084100222100002101063700001601084700001701100700001801117700001901135856003601154 2016 eng d00aSisyphus Thermalization of Photons in a Cavity-Coupled Double Quantum Dot0 aSisyphus Thermalization of Photons in a CavityCoupled Double Qua c2016/07/25 a0568010 v1173 aA strongly driven quantum system, coupled to a thermalizing bath, generically evolves into a highly non-thermal state as the external drive competes with the equilibrating force of the bath. We demonstrate a notable exception to this picture for a microwave resonator interacting with a periodically driven double quantum dot (DQD). In the limit of strong driving and long times, we show that the resonator field can be driven into a thermal state with a chemical potential given by a harmonic of the drive frequency. Such tunable chemical potentials are achievable with current devices and would have broad utility for quantum simulation in circuit quantum electrodynamics. As an example, we show how several DQDs embedded in an array of microwave resonators can induce a phase transition to a Bose-Einstein condensate of light.

1 aGullans, Michael1 aStehlik, J.1 aLiu, Y., -Y.1 aPetta, J., R.1 aTaylor, J., M. uhttp://arxiv.org/abs/1512.0124801507nas a2200229 4500008004100000245005700041210005700098260001500155300001100170490000800181520087400189100002701063700002101090700001601111700001301127700001501140700002001155700001801175700002101193700002501214856003801239 2015 eng d00aCoulomb bound states of strongly interacting photons0 aCoulomb bound states of strongly interacting photons c2015/09/16 a1236010 v1153 a We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasi-bound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wavefunction resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms. 1 aMaghrebi, Mohammad, F.1 aGullans, Michael1 aBienias, P.1 aChoi, S.1 aMartin, I.1 aFirstenberg, O.1 aLukin, M., D.1 aBüchler, H., P.1 aGorshkov, Alexey, V. uhttp://arxiv.org/abs/1505.03859v101515nas a2200181 4500008004100000245007100041210006900112260001500181300001100196490000700207520099200214100001701206700001601223700002101239700001901260700001801279856003601297 2015 eng d00aInjection Locking of a Semiconductor Double Quantum Dot Micromaser0 aInjection Locking of a Semiconductor Double Quantum Dot Micromas c2015/11/02 a0538020 v923 a Emission linewidth is an important figure of merit for masers and lasers. We recently demonstrated a semiconductor double quantum dot (DQD) micromaser where photons are generated through single electron tunneling events. Charge noise directly couples to the DQD energy levels, resulting in a maser linewidth that is more than 100 times larger than the Schawlow-Townes prediction. Here we demonstrate a linewidth narrowing of more than a factor 10 by locking the DQD emission to a coherent tone that is injected to the input port of the cavity. We measure the injection locking range as a function of cavity input power and show that it is in agreement with the Adler equation. The position and amplitude of distortion sidebands that appear outside of the injection locking range are quantitatively examined. Our results show that this unconventional maser, which is impacted by strong charge noise and electron-phonon coupling, is well described by standard laser models. 1 aLiu, Y., -Y.1 aStehlik, J.1 aGullans, Michael1 aTaylor, J., M.1 aPetta, J., R. uhttp://arxiv.org/abs/1508.0414701701nas a2200145 4500008004100000245005200041210005200093260001500145300001100160490000700171520130100178100002101479700001901500856003601519 2015 eng d00aOptical Control of Donor Spin Qubits in Silicon0 aOptical Control of Donor Spin Qubits in Silicon c2015/11/11 a1954110 v923 aWe show how to achieve optical, spin-selective transitions from the ground state to excited orbital states of group-V donors (P, As, Sb, Bi) in silicon. We consider two approaches based on either resonant, far-infrared (IR) transitions of the neutral donor or resonant, near-IR excitonic transitions. For far-IR light, we calculate the dipole matrix elements between the valley-orbit and spin-orbit split states for all the goup-V donors using effective mass theory. We then calculate the maximum rate and amount of electron-nuclear spin-polarization achievable through optical pumping with circularly polarized light. We find this approach is most promising for Bi donors due to their large spin-orbit and valley-orbit interactions. Using near-IR light, spin-selective excitation is possible for all the donors by driving a two-photon $\Lambda$-transition from the ground state to higher orbitals with even parity. We show that externally applied electric fields or strain allow similar, spin-selective $\Lambda$-transition to odd-parity excited states. We anticipate these results will be useful for future spectroscopic investigations of donors, quantum control and state preparation of donor spin qubits, and for developing a coherent interface between donor spin qubits and single photons. 1 aGullans, Michael1 aTaylor, J., M. uhttp://arxiv.org/abs/1507.0792901003nas a2200181 4500008004100000245006900041210006800110260001500178300001100193490000800204520048000212100002100692700001700713700001600730700001800746700001900764856003800783 2015 eng d00aPhonon-Assisted Gain in a Semiconductor Double Quantum Dot Maser0 aPhononAssisted Gain in a Semiconductor Double Quantum Dot Maser c2015/05/13 a1968020 v1143 aWe develop a microscopic model for the recently demonstrated double quantum dot (DQD) maser. In characterizing the gain of this device we find that, in addition to the direct stimulated emission of photons, there is a large contribution from the simultaneous emission of a photon and a phonon, i.e., the phonon sideband. We show that this phonon-assisted gain typically dominates the overall gain which leads to masing. Recent experimental data are well fit with our model. 1 aGullans, Michael1 aLiu, Y., -Y.1 aStehlik, J.1 aPetta, J., R.1 aTaylor, J., M. uhttp://arxiv.org/abs/1501.03499v301482nas a2200157 4500008004100000245006300041210006300104260001500167300001100182490000700193520103100200100001601231700002101247700001901268856003701287 2015 eng d00aQuantum Nonlinear Optics Near Optomechanical Instabilities0 aQuantum Nonlinear Optics Near Optomechanical Instabilities c2015/01/09 a0138180 v913 a Optomechanical systems provide a unique platform for observing quantum behavior of macroscopic objects. However, efforts towards realizing nonlinear behavior at the single photon level have been inhibited by the small size of the radiation pressure interaction. Here we show that it is not necessary to reach the single-photon strong-coupling regime in order to realize significant optomechanical nonlinearities. Instead, nonlinearities at the few quanta level can be achieved, even with weak-coupling, in a two-mode optomechanical system driven near instability. In this limit, we establish a new figure of merit for realizing strong nonlinearity which scales with the single-photon optomechanical coupling and the sideband resolution of the mechanical mode with respect to the cavity linewidth. We find that current devices based on optomechanical crystals, thought to be in the weak-coupling regime, can still achieve strong quantum nonlinearity; enabling deterministic interactions between single photons. 1 aXu, Xunnong1 aGullans, Michael1 aTaylor, J., M. uhttp://arxiv.org/abs/1404.3726v201150nas a2200193 4500008004100000245004800041210004800089260001500137300001400152490000800166520063700174100001700811700001600828700001600844700002100860700001900881700001800900856003800918 2015 eng d00aSemiconductor double quantum dot micromaser0 aSemiconductor double quantum dot micromaser c2015/01/15 a285 - 2870 v3473 a The coherent generation of light, from masers to lasers, relies upon the specific structure of the individual emitters that lead to gain. Devices operating as lasers in the few-emitter limit provide opportunities for understanding quantum coherent phenomena, from THz sources to quantum communication. Here we demonstrate a maser that is driven by single electron tunneling events. Semiconductor double quantum dots (DQDs) serve as a gain medium and are placed inside of a high quality factor microwave cavity. We verify maser action by comparing the statistics of the emitted microwave field above and below the maser threshold. 1 aLiu, Y., -Y.1 aStehlik, J.1 aEichler, C.1 aGullans, Michael1 aTaylor, J., M.1 aPetta, J., R. uhttp://arxiv.org/abs/1507.06359v101000nas a2200121 4500008004100000245007700041210006900118260001500187520059900202100002100801700001900822856003700841 2014 eng d00aA Quantum Network of Silicon Qubits using Mid-Infrared Graphene Plasmons0 aQuantum Network of Silicon Qubits using MidInfrared Graphene Pla c2014/07/253 a We consider a quantum network of mid-infrared, graphene plasmons coupled to the hydrogen-like excited states of group-V donors in silicon. First, we show how to use plasmon-enhanced light-matter interactions to achieve single-shot spin readout of the donor qubits via optical excitation and electrical detection of the emitted plasmons. We then show how plasmons in high mobility graphene nanoribbons can be used to achieve high-fidelity, two-qubit gates and entanglement of distant Si donor qubits. The proposed device is readily compatible with existing technology and fabrication methods. 1 aGullans, Michael1 aTaylor, J., M. uhttp://arxiv.org/abs/1407.7035v101278nas a2200205 4500008004100000245009000041210006900131260001400200490000700214520065300221100001600874700001300890700002000903700002700923700002100950700001800971700002500989700002101014856003701035 2014 eng d00aScattering resonances and bound states for strongly interacting Rydberg polaritons 0 aScattering resonances and bound states for strongly interacting c2014/11/30 v903 a We provide a theoretical framework describing slow-light polaritons interacting via atomic Rydberg states. We use a diagrammatic method to analytically derive the scattering properties of two polaritons. We identify parameter regimes where polariton-polariton interactions are repulsive. Furthermore, in the regime of attractive interactions, we identify multiple two-polariton bound states, calculate their dispersion, and study the resulting scattering resonances. Finally, the two-particle scattering properties allow us to derive the effective low-energy many-body Hamiltonian. This theoretical platform is applicable to ongoing experiments. 1 aBienias, P.1 aChoi, S.1 aFirstenberg, O.1 aMaghrebi, Mohammad, F.1 aGullans, Michael1 aLukin, M., D.1 aGorshkov, Alexey, V.1 aBüchler, H., P. uhttp://arxiv.org/abs/1402.7333v101470nas a2200205 4500008004100000245006500041210006400106260001500170300001400185490000800199520087200207100001701079700002201096700002001118700002101138700002301159700002501182700002001207856003701227 2013 eng d00aAll-Optical Switch and Transistor Gated by One Stored Photon0 aAllOptical Switch and Transistor Gated by One Stored Photon c2013/07/04 a768 - 7700 v3413 a The realization of an all-optical transistor where one 'gate' photon controls a 'source' light beam, is a long-standing goal in optics. By stopping a light pulse in an atomic ensemble contained inside an optical resonator, we realize a device in which one stored gate photon controls the resonator transmission of subsequently applied source photons. A weak gate pulse induces bimodal transmission distribution, corresponding to zero and one gate photons. One stored gate photon produces fivefold source attenuation, and can be retrieved from the atomic ensemble after switching more than one source photon. Without retrieval, one stored gate photon can switch several hundred source photons. With improved storage and retrieval efficiency, our work may enable various new applications, including photonic quantum gates, and deterministic multiphoton entanglement. 1 aChen, Wenlan1 aBeck, Kristin, M.1 aBücker, Robert1 aGullans, Michael1 aLukin, Mikhail, D.1 aTanji-Suzuki, Haruka1 aVuletic, Vladan uhttp://arxiv.org/abs/1401.3194v101759nas a2200169 4500008004100000245008100041210006900122260001400191490000700205520124300212100002101455700001801476700001901494700002101513700001801534856003701552 2013 eng d00aPreparation of Non-equilibrium Nuclear Spin States in Double Quantum Dots 0 aPreparation of Nonequilibrium Nuclear Spin States in Double Quan c2013/7/150 v883 a We theoretically study the dynamic polarization of lattice nuclear spins in GaAs double quantum dots containing two electrons. In our prior work [Phys. Rev. Lett. 104, 226807 (2010)] we identified three regimes of long-term dynamics, including the build up of a large difference in the Overhauser fields across the dots, the saturation of the nuclear polarization process associated with formation of so-called "dark states," and the elimination of the difference field. In particular, when the dots are different sizes we found that the Overhauser field becomes larger in the smaller dot. Here we present a detailed theoretical analysis of these problems including a model of the polarization dynamics and the development of a new numerical method to efficiently simulate semiclassical central-spin problems. When nuclear spin noise is included, the results agree with our prior work indicating that large difference fields and dark states are stable configurations, while the elimination of the difference field is unstable; however, in the absence of noise we find all three steady states are achieved depending on parameters. These results are in good agreement with dynamic nuclear polarization experiments in double quantum dots. 1 aGullans, Michael1 aKrich, J., J.1 aTaylor, J., M.1 aHalperin, B., I.1 aLukin, M., D. uhttp://arxiv.org/abs/1212.6953v301034nas a2200169 4500008004100000245005800041210005700099260001500156490000800171520053900179100002100718700001800739700002300757700002900780700001800809856003700827 2013 eng d00aSingle-photon nonlinear optics with graphene plasmons0 aSinglephoton nonlinear optics with graphene plasmons c2013/12/110 v1113 a We show that it is possible to realize significant nonlinear optical interactions at the few photon level in graphene nanostructures. Our approach takes advantage of the electric field enhancement associated with the strong confinement of graphene plasmons and the large intrinsic nonlinearity of graphene. Such a system could provide a powerful platform for quantum nonlinear optical control of light. As an example, we consider an integrated optical device that exploits this large nonlinearity to realize a single photon switch. 1 aGullans, Michael1 aChang, D., E.1 aKoppens, F., H. L.1 ade Abajo, F., J. García1 aLukin, M., D. uhttp://arxiv.org/abs/1309.2651v301154nas a2200205 4500008004100000245004700041210004700088260001400135490000800149520061400157100002100771700001500792700001800807700001400825700002100839700001800860700001500878700001800893856003700911 2012 eng d00aNanoplasmonic Lattices for Ultracold atoms0 aNanoplasmonic Lattices for Ultracold atoms c2012/12/60 v1093 a We propose to use sub-wavelength confinement of light associated with the near field of plasmonic systems to create nanoscale optical lattices for ultracold atoms. Our approach combines the unique coherence properties of isolated atoms with the sub-wavelength manipulation and strong light-matter interaction associated with nano-plasmonic systems. It allows one to considerably increase the energy scales in the realization of Hubbard models and to engineer effective long-range interactions in coherent and dissipative many-body dynamics. Realistic imperfections and potential applications are discussed. 1 aGullans, Michael1 aTiecke, T.1 aChang, D., E.1 aFeist, J.1 aThompson, J., D.1 aCirac, J., I.1 aZoller, P.1 aLukin, M., D. uhttp://arxiv.org/abs/1208.6293v301036nas a2200181 4500008004100000245006600041210006500107260001400172490000700186520050100193100002500694700001700719700002100736700001800757700002300775700001900798856003700817 2010 eng d00aAdiabatic preparation of many-body states in optical lattices0 aAdiabatic preparation of manybody states in optical lattices c2010/6/220 v813 a We analyze a technique for the preparation of low entropy many body states of atoms in optical lattices based on adiabatic passage. In particular, we show that this method allows preparation of strongly correlated states as stable highest energy states of Hamiltonians that have trivial ground states. As an example, we analyze the generation of antiferromagnetically ordered states by adiabatic change of a staggered field acting on the spins of bosonic atoms with ferromagnetic interactions. 1 aSorensen, Anders, S.1 aAltman, Ehud1 aGullans, Michael1 aPorto, J., V.1 aLukin, Mikhail, D.1 aDemler, Eugene uhttp://arxiv.org/abs/0906.2567v301401nas a2200217 4500008004100000245005600041210005600097260001300153490000800166520081300174100002100987700001801008700001901026700001401045700002101059700001901080700001401099700001501113700001801128856003701146 2010 eng d00aDynamic Nuclear Polarization in Double Quantum Dots0 aDynamic Nuclear Polarization in Double Quantum Dots c2010/6/40 v1043 aWe theoretically investigate the controlled dynamic polarization of lattice nuclear spins in GaAs double quantum dots containing two electrons. Three regimes of long-term dynamics are identified, including the build up of a large difference in the Overhauser fields across the dots, the saturation of the nuclear polarization process associated with formation of so-called "dark states," and the elimination of the difference field. We show that in the case of unequal dots, build up of difference fields generally accompanies the nuclear polarization process, whereas for nearly identical dots, build up of difference fields competes with polarization saturation in dark states. The elimination of the difference field does not, in general, correspond to a stable steady state of the polarization process. 1 aGullans, Michael1 aKrich, J., J.1 aTaylor, J., M.1 aBluhm, H.1 aHalperin, B., I.1 aMarcus, C., M.1 aStopa, M.1 aYacoby, A.1 aLukin, M., D. uhttp://arxiv.org/abs/1003.4508v2