TY - JOUR AB - We study a linear rotor in a bosonic bath within the angulon formalism. Our focus is on systems where isotropic or anisotropic impurity-boson interactions support a shallow bound state. To study the fate of the angulon in the vicinity of bound-state formation, we formulate a beyond-linear-coupling angulon Hamiltonian. First, we use it to study attractive, spherically symmetric impurity-boson interactions for which the linear rotor can be mapped onto a static impurity. The well-known polaron formalism provides an adequate description in this limit. Second, we consider anisotropic potentials, and show that the presence of a shallow bound state with pronounced anisotropic character leads to a many-body instability that washes out the angulon dynamics. AU - Dome, Tibor AU - Volosniev, Artem AU - Ghazaryan, Areg AU - Safari, Laleh AU - Schmidt, Richard AU - Lemeshko, Mikhail ID - 14845 IS - 1 JF - Physical Review B SN - 2469-9950 TI - Linear rotor in an ideal Bose gas near the threshold for binding VL - 109 ER - TY - JOUR AB - Coupling of orbital motion to a spin degree of freedom gives rise to various transport phenomena in quantum systems that are beyond the standard paradigms of classical physics. Here, we discuss features of spin-orbit dynamics that can be visualized using a classical model with two coupled angular degrees of freedom. Specifically, we demonstrate classical ‘spin’ filtering through our model and show that the interplay between angular degrees of freedom and dissipation can lead to asymmetric ‘spin’ transport. AU - Varshney, Atul AU - Ghazaryan, Areg AU - Volosniev, Artem ID - 15045 JF - Few-Body Systems KW - Atomic and Molecular Physics KW - and Optics SN - 1432-5411 TI - Classical ‘spin’ filtering with two degrees of freedom and dissipation VL - 65 ER - TY - JOUR AB - Brownian motion of a mobile impurity in a bath is affected by spin-orbit coupling (SOC). Here, we discuss a Caldeira-Leggett-type model that can be used to propose and interpret quantum simulators of this problem in cold Bose gases. First, we derive a master equation that describes the model and explore it in a one-dimensional (1D) setting. To validate the standard assumptions needed for our derivation, we analyze available experimental data without SOC; as a byproduct, this analysis suggests that the quench dynamics of the impurity is beyond the 1D Bose-polaron approach at temperatures currently accessible in a cold-atom laboratory—motion of the impurity is mainly driven by dissipation. For systems with SOC, we demonstrate that 1D spin-orbit coupling can be gauged out even in the presence of dissipation—the information about SOC is incorporated in the initial conditions. Observables sensitive to this information (such as spin densities) can be used to study formation of steady spin polarization domains during quench dynamics. AU - Ghazaryan, Areg AU - Cappellaro, Alberto AU - Lemeshko, Mikhail AU - Volosniev, Artem ID - 12534 IS - 1 JF - Physical Review Research SN - 2643-1564 TI - Dissipative dynamics of an impurity with spin-orbit coupling VL - 5 ER - TY - JOUR AB - We show that the simplest of existing molecules—closed-shell diatomics not interacting with one another—host topological charges when driven by periodic far-off-resonant laser pulses. A periodically kicked molecular rotor can be mapped onto a “crystalline” lattice in angular momentum space. This allows us to define quasimomenta and the band structure in the Floquet representation, by analogy with the Bloch waves of solid-state physics. Applying laser pulses spaced by 1/3 of the molecular rotational period creates a lattice with three atoms per unit cell with staggered hopping. Within the synthetic dimension of the laser strength, we discover Dirac cones with topological charges. These Dirac cones, topologically protected by reflection and time-reversal symmetry, are reminiscent of (although not equivalent to) that seen in graphene. They—and the corresponding edge states—are broadly tunable by adjusting the laser strength and can be observed in present-day experiments by measuring molecular alignment and populations of rotational levels. This paves the way to study controllable topological physics in gas-phase experiments with small molecules as well as to classify dynamical molecular states by their topological invariants. AU - Karle, Volker AU - Ghazaryan, Areg AU - Lemeshko, Mikhail ID - 12788 IS - 10 JF - Physical Review Letters SN - 0031-9007 TI - Topological charges of periodically kicked molecules VL - 130 ER - TY - JOUR AB - Motivated by the recent discoveries of superconductivity in bilayer and trilayer graphene, we theoretically investigate superconductivity and other interaction-driven phases in multilayer graphene stacks. To this end, we study the density of states of multilayer graphene with up to four layers at the single-particle band structure level in the presence of a transverse electric field. Among the considered structures, tetralayer graphene with rhombohedral (ABCA) stacking reaches the highest density of states. We study the phases that can arise in ABCA graphene by tuning the carrier density and transverse electric field. For a broad region of the tuning parameters, the presence of strong Coulomb repulsion leads to a spontaneous spin and valley symmetry breaking via Stoner transitions. Using a model that incorporates the spontaneous spin and valley polarization, we explore the Kohn-Luttinger mechanism for superconductivity driven by repulsive Coulomb interactions. We find that the strongest superconducting instability is in the p-wave channel, and occurs in proximity to the onset of Stoner transitions. Interestingly, we find a range of densities and transverse electric fields where superconductivity develops out of a strongly corrugated, singly connected Fermi surface in each valley, leading to a topologically nontrivial chiral p+ip superconducting state with an even number of copropagating chiral Majorana edge modes. Our work establishes ABCA-stacked tetralayer graphene as a promising platform for observing strongly correlated physics and topological superconductivity. AU - Ghazaryan, Areg AU - Holder, Tobias AU - Berg, Erez AU - Serbyn, Maksym ID - 12790 IS - 10 JF - Physical Review B SN - 2469-9950 TI - Multilayer graphenes as a platform for interaction-driven physics and topological superconductivity VL - 107 ER - TY - JOUR AB - The development of two-dimensional materials has resulted in a diverse range of novel, high-quality compounds with increasing complexity. A key requirement for a comprehensive quantitative theory is the accurate determination of these materials' band structure parameters. However, this task is challenging due to the intricate band structures and the indirect nature of experimental probes. In this work, we introduce a general framework to derive band structure parameters from experimental data using deep neural networks. We applied our method to the penetration field capacitance measurement of trilayer graphene, an effective probe of its density of states. First, we demonstrate that a trained deep network gives accurate predictions for the penetration field capacitance as a function of tight-binding parameters. Next, we use the fast and accurate predictions from the trained network to automatically determine tight-binding parameters directly from experimental data, with extracted parameters being in a good agreement with values in the literature. We conclude by discussing potential applications of our method to other materials and experimental techniques beyond penetration field capacitance. AU - Henderson, Paul M AU - Ghazaryan, Areg AU - Zibrov, Alexander A. AU - Young, Andrea F. AU - Serbyn, Maksym ID - 14320 IS - 12 JF - Physical Review B SN - 2469-9950 TI - Deep learning extraction of band structure parameters from density of states: A case study on trilayer graphene VL - 108 ER - TY - JOUR AB - Coherent control and manipulation of quantum degrees of freedom such as spins forms the basis of emerging quantum technologies. In this context, the robust valley degree of freedom and the associated valley pseudospin found in two-dimensional transition metal dichalcogenides is a highly attractive platform. Valley polarization and coherent superposition of valley states have been observed in these systems even up to room temperature. Control of valley coherence is an important building block for the implementation of valley qubit. Large magnetic fields or high-power lasers have been used in the past to demonstrate the control (initialization and rotation) of the valley coherent states. Here, the control of layer–valley coherence via strong coupling of valley excitons in bilayer WS2 to microcavity photons is demonstrated by exploiting the pseudomagnetic field arising in optical cavities owing to the transverse electric–transverse magnetic (TE–TM)mode splitting. The use of photonic structures to generate pseudomagnetic fields which can be used to manipulate exciton-polaritons presents an attractive approach to control optical responses without the need for large magnets or high-intensity optical pump powers. AU - Khatoniar, Mandeep AU - Yama, Nicholas AU - Ghazaryan, Areg AU - Guddala, Sriram AU - Ghaemi, Pouyan AU - Majumdar, Kausik AU - Menon, Vinod ID - 12836 IS - 13 JF - Advanced Optical Materials TI - Optical manipulation of Layer–Valley coherence via strong exciton–photon coupling in microcavities VL - 11 ER - TY - JOUR AB - Traditionally, nuclear spin is not considered to affect biological processes. Recently, this has changed as isotopic fractionation that deviates from classical mass dependence was reported both in vitro and in vivo. In these cases, the isotopic effect correlates with the nuclear magnetic spin. Here, we show nuclear spin effects using stable oxygen isotopes (16O, 17O, and 18O) in two separate setups: an artificial dioxygen production system and biological aquaporin channels in cells. We observe that oxygen dynamics in chiral environments (in particular its transport) depend on nuclear spin, suggesting future applications for controlled isotope separation to be used, for instance, in NMR. To demonstrate the mechanism behind our findings, we formulate theoretical models based on a nuclear-spin-enhanced switch between electronic spin states. Accounting for the role of nuclear spin in biology can provide insights into the role of quantum effects in living systems and help inspire the development of future biotechnology solutions. AU - Vardi, Ofek AU - Maroudas-Sklare, Naama AU - Kolodny, Yuval AU - Volosniev, Artem AU - Saragovi, Amijai AU - Galili, Nir AU - Ferrera, Stav AU - Ghazaryan, Areg AU - Yuran, Nir AU - Affek, Hagit P. AU - Luz, Boaz AU - Goldsmith, Yonaton AU - Keren, Nir AU - Yochelis, Shira AU - Halevy, Itay AU - Lemeshko, Mikhail AU - Paltiel, Yossi ID - 14037 IS - 32 JF - Proceedings of the National Academy of Sciences of the United States of America TI - Nuclear spin effects in biological processes VL - 120 ER - TY - JOUR AB - We present a minimal model of ferroelectric large polarons, which are suggested as one of the mechanisms responsible for the unique charge transport properties of hybrid perovskites. We demonstrate that short-ranged charge–rotor interactions lead to long-range ferroelectric ordering of rotors, which strongly affects the carrier mobility. In the nonperturbative regime, where our theory cannot be reduced to any of the earlier models, we reveal that the polaron is characterized by large coherence length and a roughly tenfold increase of the effective mass as compared to the bare mass. These results are in good agreement with other theoretical predictions for ferroelectric polarons. Our model establishes a general phenomenological framework for ferroelectric polarons providing the starting point for future studies of their role in the transport properties of hybrid organic-inorganic perovskites. AU - Koutentakis, Georgios AU - Ghazaryan, Areg AU - Lemeshko, Mikhail ID - 14486 IS - 4 JF - Physical Review Research SN - 2643-1564 TI - Rotor lattice model of ferroelectric large polarons VL - 5 ER - TY - JOUR AB - The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when interactions with other particles become relevant. Here, we illustrate such an extension for a particle in an Aharonov-Bohm ring subject to interactions with a weakly interacting Bose gas. We show that the ground state of the system can be described using the Bose-polaron concept—a particle dressed by interactions with a bosonic environment. We connect the energy spectrum to the effective mass of the polaron, and demonstrate how to change currents in the system by tuning boson-particle interactions. Our results suggest the Aharonov-Bohm ring as a platform for studying coherence and few- to many-body crossover of quasi-particles that arise from an impurity immersed in a medium. AU - Brauneis, Fabian AU - Ghazaryan, Areg AU - Hammer, Hans-Werner AU - Volosniev, Artem ID - 14246 JF - Communications Physics KW - General Physics and Astronomy SN - 2399-3650 TI - Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux VL - 6 ER - TY - JOUR AB - We demonstrate that a sodium dimer, Na2(13Σ+u), residing on the surface of a helium nanodroplet, can be set into rotation by a nonresonant 1.0 ps infrared laser pulse. The time-dependent degree of alignment measured, exhibits a periodic, gradually decreasing structure that deviates qualitatively from that expected for gas-phase dimers. Comparison to alignment dynamics calculated from the time-dependent rotational Schrödinger equation shows that the deviation is due to the alignment dependent interaction between the dimer and the droplet surface. This interaction confines the dimer to the tangential plane of the droplet surface at the point where it resides and is the reason that the observed alignment dynamics is also well described by a 2D quantum rotor model. AU - Kranabetter, Lorenz AU - Kristensen, Henrik H. AU - Ghazaryan, Areg AU - Schouder, Constant A. AU - Chatterley, Adam S. AU - Janssen, Paul AU - Jensen, Frank AU - Zillich, Robert E. AU - Lemeshko, Mikhail AU - Stapelfeldt, Henrik ID - 14238 IS - 5 JF - Physical Review Letters SN - 0031-9007 TI - Nonadiabatic laser-induced alignment dynamics of molecules on a surface VL - 131 ER - TY - JOUR AB - Bernal-stacked multilayer graphene is a versatile platform to explore quantum transport phenomena and interaction physics due to its exceptional tunability via electrostatic gating. For instance, upon applying a perpendicular electric field, its band structure exhibits several off-center Dirac points (so-called Dirac gullies) in each valley. Here, the formation of Dirac gullies and the interaction-induced breakdown of gully coherence is explored via magnetotransport measurements in high-quality Bernal-stacked (ABA) trilayer graphene. At zero magnetic field, multiple Lifshitz transitions indicating the formation of Dirac gullies are identified. In the quantum Hall regime, the emergence of Dirac gullies is evident as an increase in Landau level degeneracy. When tuning both electric and magnetic fields, electron–electron interactions can be controllably enhanced until, beyond critical electric and magnetic fields, the gully degeneracy is eventually lifted. The arising correlated ground state is consistent with a previously predicted nematic phase that spontaneously breaks the rotational gully symmetry. AU - Winterer, Felix AU - Seiler, Anna M. AU - Ghazaryan, Areg AU - Geisenhof, Fabian R. AU - Watanabe, Kenji AU - Taniguchi, Takashi AU - Serbyn, Maksym AU - Weitz, R. Thomas ID - 11379 IS - 8 JF - Nano Letters SN - 15306984 TI - Spontaneous gully-polarized quantum hall states in ABA trilayer graphene VL - 22 ER - TY - JOUR AB - We demonstrate the formation of robust zero-energy modes close to magnetic impurities in the iron-based superconductor FeSe1-z Tez. We find that the Zeeman field generated by the impurity favors a spin-triplet interorbital pairing as opposed to the spin-singlet intraorbital pairing prevalent in the bulk. The preferred spin-triplet pairing preserves time-reversal symmetry and is topological, as robust, topologically protected zero modes emerge at the boundary between regions with different pairing states. Moreover, the zero modes form Kramers doublets that are insensitive to the direction of the spin polarization or to the separation between impurities. We argue that our theoretical results are consistent with recent experimental measurements on FeSe1-z Tez. AU - Ghazaryan, Areg AU - Kirmani, Ammar AU - Fernandes, Rafael M. AU - Ghaemi, Pouyan ID - 12139 IS - 20 JF - Physical Review B SN - 2469-9950 TI - Anomalous Shiba states in topological iron-based superconductors VL - 106 ER - TY - JOUR AB - Superconductor-semiconductor hybrid devices are at the heart of several proposed approaches to quantum information processing, but their basic properties remain to be understood. We embed a twodimensional Al-InAs hybrid system in a resonant microwave circuit, probing the breakdown of superconductivity due to an applied magnetic field. We find a fingerprint from the two-component nature of the hybrid system, and quantitatively compare with a theory that includes the contribution of intraband p±ip pairing in the InAs, as well as the emergence of Bogoliubov-Fermi surfaces due to magnetic field. Separately resolving the Al and InAs contributions allows us to determine the carrier density and mobility in the InAs. AU - Phan, Duc T AU - Senior, Jorden L AU - Ghazaryan, Areg AU - Hatefipour, M. AU - Strickland, W. M. AU - Shabani, J. AU - Serbyn, Maksym AU - Higginbotham, Andrew P ID - 10851 IS - 10 JF - Physical Review Letters KW - General Physics and Astronomy SN - 0031-9007 TI - Detecting induced p±ip pairing at the Al-InAs interface with a quantum microwave circuit VL - 128 ER - TY - JOUR AB - We study an effective one-dimensional quantum model that includes friction and spin-orbit coupling (SOC), and show that the model exhibits spin polarization when both terms are finite. Most important, strong spin polarization can be observed even for moderate SOC, provided that the friction is strong. Our findings might help to explain the pronounced effect of chirality on spin distribution and transport in chiral molecules. In particular, our model implies static magnetic properties of a chiral molecule, which lead to Shiba-like states when a molecule is placed on a superconductor, in accordance with recent experimental data. AU - Volosniev, Artem AU - Alpern, Hen AU - Paltiel, Yossi AU - Millo, Oded AU - Lemeshko, Mikhail AU - Ghazaryan, Areg ID - 9770 IS - 2 JF - Physical Review B SN - 2469-9950 TI - Interplay between friction and spin-orbit coupling as a source of spin polarization VL - 104 ER - TY - JOUR AB - Ferromagnetism is most common in transition metal compounds but may also arise in low-density two-dimensional electron systems, with signatures observed in silicon, III-V semiconductor systems, and graphene moiré heterostructures. Here we show that gate-tuned van Hove singularities in rhombohedral trilayer graphene drive the spontaneous ferromagnetic polarization of the electron system into one or more spin- and valley flavors. Using capacitance measurements on graphite-gated van der Waals heterostructures, we find a cascade of density- and electronic displacement field tuned phase transitions marked by negative electronic compressibility. The transitions define the boundaries between phases where quantum oscillations have either four-fold, two-fold, or one-fold degeneracy, associated with a spin and valley degenerate normal metal, spin-polarized `half-metal', and spin and valley polarized `quarter metal', respectively. For electron doping, the salient features are well captured by a phenomenological Stoner model with a valley-anisotropic Hund's coupling, likely arising from interactions at the lattice scale. For hole filling, we observe a richer phase diagram featuring a delicate interplay of broken symmetries and transitions in the Fermi surface topology. Finally, by rotational alignment of a hexagonal boron nitride substrate to induce a moiré superlattice, we find that the superlattice perturbs the preexisting isospin order only weakly, leaving the basic phase diagram intact while catalyzing the formation of topologically nontrivial gapped states whenever itinerant half- or quarter metal states occur at half- or quarter superlattice band filling. Our results show that rhombohedral trilayer graphene is an ideal platform for well-controlled tests of many-body theory and reveal magnetism in moiré materials to be fundamentally itinerant in nature. AU - Zhou, Haoxin AU - Xie, Tian AU - Ghazaryan, Areg AU - Holder, Tobias AU - Ehrets, James R. AU - Spanton, Eric M. AU - Taniguchi, Takashi AU - Watanabe, Kenji AU - Berg, Erez AU - Serbyn, Maksym AU - Young, Andrea F. ID - 10025 JF - Nature KW - condensed matter - mesoscale and nanoscale physics KW - condensed matter - strongly correlated electrons KW - multidisciplinary SN - 0028-0836 TI - Half and quarter metals in rhombohedral trilayer graphene ER - TY - JOUR AB - We show that in a two-dimensional electron gas with an annular Fermi surface, long-range Coulomb interactions can lead to unconventional superconductivity by the Kohn-Luttinger mechanism. Superconductivity is strongly enhanced when the inner and outer Fermi surfaces are close to each other. The most prevalent state has chiral p-wave symmetry, but d-wave and extended s-wave pairing are also possible. We discuss these results in the context of rhombohedral trilayer graphene, where superconductivity was recently discovered in regimes where the normal state has an annular Fermi surface. Using realistic parameters, our mechanism can account for the order of magnitude of Tc, as well as its trends as a function of electron density and perpendicular displacement field. Moreover, it naturally explains some of the outstanding puzzles in this material, that include the weak temperature dependence of the resistivity above Tc, and the proximity of spin singlet superconductivity to the ferromagnetic phase. AU - Ghazaryan, Areg AU - Holder, Tobias AU - Serbyn, Maksym AU - Berg, Erez ID - 10527 IS - 24 JF - Physical Review Letters KW - general physics and astronomy SN - 0031-9007 TI - Unconventional superconductivity in systems with annular Fermi surfaces: Application to rhombohedral trilayer graphene VL - 127 ER - TY - JOUR AB - The surface states of 3D topological insulators in general have negligible quantum oscillations (QOs) when the chemical potential is tuned to the Dirac points. In contrast, we find that topological Kondo insulators (TKIs) can support surface states with an arbitrarily large Fermi surface (FS) when the chemical potential is pinned to the Dirac point. We illustrate that these FSs give rise to finite-frequency QOs, which can become comparable to the extremal area of the unhybridized bulk bands. We show that this occurs when the crystal symmetry is lowered from cubic to tetragonal in a minimal two-orbital model. We label such surface modes as 'shadow surface states'. Moreover, we show that the sufficient next-nearest neighbor out-of-plane hybridization leading to shadow surface states can be self-consistently stabilized for tetragonal TKIs. Consequently, shadow surface states provide an important example of high-frequency QOs beyond the context of cubic TKIs. AU - Ghazaryan, Areg AU - Nica, Emilian M. AU - Erten, Onur AU - Ghaemi, Pouyan ID - 10628 IS - 12 JF - New Journal of Physics SN - 1367-2630 TI - Shadow surface states in topological Kondo insulators VL - 23 ER - TY - GEN AB - Superconductor-semiconductor hybrids are platforms for realizing effective p-wave superconductivity. Spin-orbit coupling, combined with the proximity effect, causes the two-dimensional semiconductor to inherit p±ip intraband pairing, and application of magnetic field can then result in transitions to the normal state, partial Bogoliubov Fermi surfaces, or topological phases with Majorana modes. Experimentally probing the hybrid superconductor-semiconductor interface is challenging due to the shunting effect of the conventional superconductor. Consequently, the nature of induced pairing remains an open question. Here, we use the circuit quantum electrodynamics architecture to probe induced superconductivity in a two dimensional Al-InAs hybrid system. We observe a strong suppression of superfluid density and enhanced dissipation driven by magnetic field, which cannot be accounted for by the depairing theory of an s-wave superconductor. These observations are explained by a picture of independent intraband p±ip superconductors giving way to partial Bogoliubov Fermi surfaces, and allow for the first characterization of key properties of the hybrid superconducting system. AU - Phan, Duc T AU - Senior, Jorden L AU - Ghazaryan, Areg AU - Hatefipour, M. AU - Strickland, W. M. AU - Shabani, J. AU - Serbyn, Maksym AU - Higginbotham, Andrew P ID - 10029 T2 - arXiv TI - Breakdown of induced p±ip pairing in a superconductor-semiconductor hybrid ER - TY - JOUR AB - Nature creates electrons with two values of the spin projection quantum number. In certain applications, it is important to filter electrons with one spin projection from the rest. Such filtering is not trivial, since spin-dependent interactions are often weak, and cannot lead to any substantial effect. Here we propose an efficient spin filter based upon scattering from a two-dimensional crystal, which is made of aligned point magnets. The polarization of the outgoing electron flux is controlled by the crystal, and reaches maximum at specific values of the parameters. In our scheme, polarization increase is accompanied by higher reflectivity of the crystal. High transmission is feasible in scattering from a quantum cavity made of two crystals. Our findings can be used for studies of low-energy spin-dependent scattering from two-dimensional ordered structures made of magnetic atoms or aligned chiral molecules. AU - Ghazaryan, Areg AU - Lemeshko, Mikhail AU - Volosniev, Artem ID - 8652 JF - Communications Physics SN - 2399-3650 TI - Filtering spins by scattering from a lattice of point magnets VL - 3 ER - TY - JOUR AB - Organic materials are known to feature long spin-diffusion times, originating in a generally small spin–orbit coupling observed in these systems. From that perspective, chiral molecules acting as efficient spin selectors pose a puzzle that attracted a lot of attention in recent years. Here, we revisit the physical origins of chiral-induced spin selectivity (CISS) and propose a simple analytic minimal model to describe it. The model treats a chiral molecule as an anisotropic wire with molecular dipole moments aligned arbitrarily with respect to the wire’s axes and is therefore quite general. Importantly, it shows that the helical structure of the molecule is not necessary to observe CISS and other chiral nonhelical molecules can also be considered as potential candidates for the CISS effect. We also show that the suggested simple model captures the main characteristics of CISS observed in the experiment, without the need for additional constraints employed in the previous studies. The results pave the way for understanding other related physical phenomena where the CISS effect plays an essential role. AU - Ghazaryan, Areg AU - Paltiel, Yossi AU - Lemeshko, Mikhail ID - 7968 IS - 21 JF - The Journal of Physical Chemistry C SN - 1932-7447 TI - Analytic model of chiral-induced spin selectivity VL - 124 ER - TY - JOUR AB - Dipolar (or spatially indirect) excitons (IXs) in semiconductor double quantum well (DQW) subjected to an electric field are neutral species with a dipole moment oriented perpendicular to the DQW plane. Here, we theoretically study interactions between IXs in stacked DQW bilayers, where the dipolar coupling can be either attractive or repulsive depending on the relative positions of the particles. By using microscopic band structure calculations to determine the electronic states forming the excitons, we show that the attractive dipolar interaction between stacked IXs deforms their electronic wave function, thereby increasing the inter-DQW interaction energy and making the IX even more electrically polarizable. Many-particle interaction effects are addressed by considering the coupling between a single IX in one of the DQWs to a cloud of IXs in the other DQW, which is modeled either as a closed-packed lattice or as a continuum IX fluid. We find that the lattice model yields IX interlayer binding energies decreasing with increasing lattice density. This behavior is due to the dominating role of the intra-DQW dipolar repulsion, which prevents more than one exciton from entering the attractive region of the inter-DQW coupling. Finally, both models shows that the single IX distorts the distribution of IXs in the adjacent DQW, thus inducing the formation of an IX dipolar polaron (dipolaron). While the interlayer binding energy reduces with IX density for lattice dipolarons, the continuous polaron model predicts a nonmonotonous dependence on density in semiquantitative agreement with a recent experimental study [cf. Hubert et al., Phys. Rev. X 9, 021026 (2019)]. AU - Hubert, C. AU - Cohen, K. AU - Ghazaryan, Areg AU - Lemeshko, Mikhail AU - Rapaport, R. AU - Santos, P. V. ID - 8588 IS - 4 JF - Physical Review B SN - 2469-9950 TI - Attractive interactions, molecular complexes, and polarons in coupled dipolar exciton fluids VL - 102 ER - TY - JOUR AB - One of the hallmarks of quantum statistics, tightly entwined with the concept of topological phases of matter, is the prediction of anyons. Although anyons are predicted to be realized in certain fractional quantum Hall systems, they have not yet been unambiguously detected in experiment. Here we introduce a simple quantum impurity model, where bosonic or fermionic impurities turn into anyons as a consequence of their interaction with the surrounding many-particle bath. A cloud of phonons dresses each impurity in such a way that it effectively attaches fluxes or vortices to it and thereby converts it into an Abelian anyon. The corresponding quantum impurity model, first, provides a different approach to the numerical solution of the many-anyon problem, along with a concrete perspective of anyons as emergent quasiparticles built from composite bosons or fermions. More importantly, the model paves the way toward realizing anyons using impurities in crystal lattices as well as ultracold gases. In particular, we consider two heavy electrons interacting with a two-dimensional lattice crystal in a magnetic field, and show that when the impurity-bath system is rotated at the cyclotron frequency, impurities behave as anyons as a consequence of the angular momentum exchange between the impurities and the bath. A possible experimental realization is proposed by identifying the statistics parameter in terms of the mean-square distance of the impurities and the magnetization of the impurity-bath system, both of which are accessible to experiment. Another proposed application is impurities immersed in a two-dimensional weakly interacting Bose gas. AU - Yakaboylu, Enderalp AU - Ghazaryan, Areg AU - Lundholm, D. AU - Rougerie, N. AU - Lemeshko, Mikhail AU - Seiringer, Robert ID - 8769 IS - 14 JF - Physical Review B SN - 2469-9950 TI - Quantum impurity model for anyons VL - 102 ER - TY - JOUR AB - In the superconducting regime of FeTe(1−x)Sex, there exist two types of vortices which are distinguished by the presence or absence of zero-energy states in their core. To understand their origin, we examine the interplay of Zeeman coupling and superconducting pairings in three-dimensional metals with band inversion. Weak Zeeman fields are found to suppress intraorbital spin-singlet pairing, known to localize the states at the ends of the vortices on the surface. On the other hand, an orbital-triplet pairing is shown to be stable against Zeeman interactions, but leads to delocalized zero-energy Majorana modes which extend through the vortex. In contrast, the finite-energy vortex modes remain localized at the vortex ends even when the pairing is of orbital-triplet form. Phenomenologically, this manifests as an observed disappearance of zero-bias peaks within the cores of topological vortices upon an increase of the applied magnetic field. The presence of magnetic impurities in FeTe(1−x)Sex, which are attracted to the vortices, would lead to such Zeeman-induced delocalization of Majorana modes in a fraction of vortices that capture a large enough number of magnetic impurities. Our results provide an explanation for the dichotomy between topological and nontopological vortices recently observed in FeTe(1−x)Sex. AU - Ghazaryan, Areg AU - Lopes, P. L.S. AU - Hosur, Pavan AU - Gilbert, Matthew J. AU - Ghaemi, Pouyan ID - 7428 IS - 2 JF - Physical Review B SN - 24699950 TI - Effect of Zeeman coupling on the Majorana vortex modes in iron-based topological superconductors VL - 101 ER - TY - CONF AB - We demonstrate robust retention of valley coherence and its control via polariton pseudospin precession through the optical TE-TM splitting in bilayer WS2 microcavity exciton polaritons at room temperature. AU - Khatoniar, Mandeep AU - Yama, Nicholas AU - Ghazaryan, Areg AU - Guddala, Sriram AU - Ghaemi, Pouyan AU - Menon, Vinod ID - 6646 SN - 9781943580576 T2 - CLEO: Applications and Technology TI - Room temperature control of valley coherence in bilayer WS2 exciton polaritons ER -