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Electron hydrodynamics of anomalous Hall materials Hasdeo, Eddwi Hesky ; Ekström, Carl Johan Ingvar ; Idrisov, Edvin et al in Physical Review. B (2021), 103(12), 125106 We study two-dimensional electron systems in the hydrodynamic regime. We show that a geometrical Berry curvature modifies the effective Navier-Stokes equation for viscous electron flow in topological ... [more ▼] We study two-dimensional electron systems in the hydrodynamic regime. We show that a geometrical Berry curvature modifies the effective Navier-Stokes equation for viscous electron flow in topological materials. For small electric fields, the Hall current becomes negligible compared to the viscous longitudinal current. In this regime, we highlight an unconventional Poiseuille flow with an asymmetric profile and a deviation of the maximum of the current from the center of the system. In a two-dimensional infinite geometry, the Berry curvature leads to current whirlpools and an asymmetry of potential profile. This phenomenon can be probed by measuring the asymmetric non-local resistance profile. [less ▲] Detailed reference viewed: 34 (8 UL)Optical properties of topological flat and dispersive bands Habibi, Alireza ; ; et al E-print/Working paper (2021) We study the optical properties of topological flat and dispersive bands. Due to their topological nature, there exists an anomalous Hall response which gives rise to a transverse current without applied ... [more ▼] We study the optical properties of topological flat and dispersive bands. Due to their topological nature, there exists an anomalous Hall response which gives rise to a transverse current without applied magnetic field. The dynamical Hall conductivity of systems with flat bands exhibits a sign change when the excitation energy is on resonance with the band gap, similar to the magnetotransport Hall conductivity profile. The sign change of the Hall conductivity is located at the frequency corresponding to the singularity of the joint density of states, i.e., the van Hove singularity (VHS). For perfectly flat bands, this VHS energy matches the band gap. On the other hand, in the case of dispersive bands, the VHS energy is located above the band gap. As a result, the two features of the Hall conductivity, i.e., the resonant feature at the band gap and the sign change at the VHS energy, become separated. This anomalous Hall response rotates the polarization of an electric field and can be detected in the reflected and transmitted waves, as Kerr and Faraday rotations, respectively, thus allowing a simple optical characterization of topological flat bands. [less ▲] Detailed reference viewed: 18 (4 UL)Kerr effect in tilted nodal loop semimetals Ekström, Carl Johan Ingvar ; Hasdeo, Eddwi Hesky ; Farias, Maria Belen et al E-print/Working paper (2021) We investigate the optical activity of tilted nodal loop semimetals. We calculate the full conductivity matrix for a band structure containing a nodal loop with possible tilt in the x−y plane, which ... [more ▼] We investigate the optical activity of tilted nodal loop semimetals. We calculate the full conductivity matrix for a band structure containing a nodal loop with possible tilt in the x−y plane, which allows us to study the Kerr rotation and ellipticity both for a thin film and a bulk material. We find signatures in the Kerr signal that give direct information about the tilt velocity and direction, the radius of the nodal loop and the internal chemical potential of the system. These findings should serve as guide to understanding optical measurements of nodal loop semimetals and as an additional tool to characterize them. [less ▲] Detailed reference viewed: 15 (1 UL)Heat transport in overdamped quantum systems Salehi Kadijani, Mohammad Sadeq ; Schmidt, Thomas ; Esposito, Massimiliano et al in Physical Review. B (2020) Detailed reference viewed: 46 (5 UL)In-plane magnetic field-driven symmetry breaking in topological insulator-based three-terminal junctions ; ; Schmidt, Thomas et al E-print/Working paper (2020) Detailed reference viewed: 16 (0 UL)Current correlations of Cooper-pair tunneling into a quantum Hall system Michelsen, Andreas Nicolai Bock ; Schmidt, Thomas ; Idrisov, Edvin in Physical Review. B, Condensed Matter and Materials Physics (2020), 102 Detailed reference viewed: 25 (3 UL)Casimir force between Weyl semimetals in a chiral medium Farias, Maria Belen ; ; Schmidt, Thomas in Physical Review. B (2020), 101 Detailed reference viewed: 26 (5 UL)Transport properties of coupled Majorana bound states in the Coulomb blockade regime Ekström, Carl Johan Ingvar ; ; Schmidt, Thomas in Physical Review. B, Condensed Matter and Materials Physics (2020) Topologically protected qubits based on nanostructures hosting Majorana bound states (MBSs) hold great promise for fault-tolerant quantum computing. We study the transport properties of nanowire networks ... [more ▼] Topologically protected qubits based on nanostructures hosting Majorana bound states (MBSs) hold great promise for fault-tolerant quantum computing. We study the transport properties of nanowire networks hosting MBSs with a focus on the effects of the charging energy and the overlap between neighboring MBSs in short mesoscopic samples. In particular, we investigate structures hosting four MBSs such as T junctions and Majorana boxes. Using a master equation in the Markovian approximation, we discuss the leading transport processes mediated by the MBSs. Single-electron tunneling and processes involving creation and annihilation of Cooper pairs dominate in the sequential-tunneling limit. In the cotunneling regime the charge in the MBSs is fixed and transport is governed by transitions via virtual intermediate states. Our results show that four-terminal measurements in the T junction and Majorana box geometries can be useful tools for the characterization of the properties of MBSs with finite overlaps and charging energy. [less ▲] Detailed reference viewed: 51 (4 UL)Bosonization for Fermions and Parafermions Schmidt, Thomas in European Physical Journal. Special Topics (2020), 229 Parafermions are fractional excitations which can be regarded as generalizations of Majorana bound states, but in contrast to the latter they require electron-electron interactions. Compared to Majorana ... [more ▼] Parafermions are fractional excitations which can be regarded as generalizations of Majorana bound states, but in contrast to the latter they require electron-electron interactions. Compared to Majorana bound states, they offer richer non-Abelian braiding statistics, and have thus been proposed as building blocks for topologically protected universal quantum computation. In this review, we provide a pedagogical introduction to the field of parafermion bound states in one-dimensional systems. We present the necessary theoretical tools for their study, in particular bosonization and the renormalization-group technique, and show how those can be applied to study parafermions. [less ▲] Detailed reference viewed: 70 (4 UL)Universal Hall conductance scaling in non-Hermitian Chern insulators Groenendijk, Solofo ; Schmidt, Thomas ; E-print/Working paper (2020) Detailed reference viewed: 18 (0 UL)Heat transport in overdamped quantum systems ; Schmidt, Thomas ; Esposito, Massimiliano et al in Physical Review. B (2020), 102 Detailed reference viewed: 21 (1 UL)Parafermion braiding in fractional quantum Hall edge states with a finite chemical potential Groenendijk, Solofo ; ; et al in Physical Review. B, Condensed Matter and Materials Physics (2019), 100 Parafermions are non-Abelian anyons which generalize Majorana fermions and hold great promise for topological quantum computation. We study the braiding of Z2n parafermions which have been predicted to ... [more ▼] Parafermions are non-Abelian anyons which generalize Majorana fermions and hold great promise for topological quantum computation. We study the braiding of Z2n parafermions which have been predicted to emerge as localized zero modes in fractional quantum Hall systems at filling factor ν=1/n (n odd). Using a combination of bosonization and refermionization, we calculate the energy splitting as a function of distance and chemical potential for a pair of parafermions separated by a gapped region. Braiding of parafermions in quantum Hall edge states can be implemented by repeated fusion and nucleation of parafermion pairs. We simulate the conventional braiding protocol of parafermions numerically, taking into account the finite separation and finite chemical potential. We show that a nonzero chemical potential poses challenges for the adiabaticity of the braiding process because it leads to accidental crossings in the spectrum. To remedy this, we propose an improved braiding protocol which avoids those degeneracies. [less ▲] Detailed reference viewed: 64 (2 UL)Entropy production in one-dimensional quantum fluids Idrisov, Edvin ; Schmidt, Thomas in Physical Review. B (2019) Detailed reference viewed: 47 (3 UL)Mechanical Resonances of Mobile Impurities in a One-Dimensional Quantum Fluid Schmidt, Thomas ; ; et al in Physical Review Letters (2019), 123 We study a one-dimensional interacting quantum liquid hosting a pair of mobile impurities causing backscattering. We determine the effective retarded interaction between the two impurities mediated by the ... [more ▼] We study a one-dimensional interacting quantum liquid hosting a pair of mobile impurities causing backscattering. We determine the effective retarded interaction between the two impurities mediated by the liquid. We show that for strong backscattering this interaction gives rise to resonances and antiresonances in the finite-frequency mobility of the impurity pair. At the antiresonances, the two impurities remain at rest even when driven by a (small) external force. At the resonances, their synchronous motion follows the external drive in phase and reaches maximum amplitude. Using a perturbative renormalization group analysis in quantum tunneling across the impurities, we study the range of validity of our model. We predict that these mechanical antiresonances are observable in experiments on ultracold atom gases confined to one dimension. [less ▲] Detailed reference viewed: 86 (0 UL)Disorder-driven exceptional lines and Fermi ribbons in tilted nodal-line semimetals ; ; et al in Physical Review. B, Condensed Matter (2019), 99 We consider the impact of disorder on the spectrum of three-dimensional nodal-line semimetals. We show that the combination of disorder and a tilted spectrum naturally leads to a non-Hermitian self-energy ... [more ▼] We consider the impact of disorder on the spectrum of three-dimensional nodal-line semimetals. We show that the combination of disorder and a tilted spectrum naturally leads to a non-Hermitian self-energy contribution that can split a nodal line into a pair of exceptional lines. These exceptional lines form the boundary of an open and orientable bulk Fermi ribbon in reciprocal space on which the energy gap vanishes. We find that the orientation and shape of such a disorder-induced bulk Fermi ribbon is controlled by the tilt direction and the disorder properties, which can also be exploited to realize a twisted bulk Fermi ribbon with nontrivial winding number. Our results put forward a paradigm for the exploration of non-Hermitian topological phases of matter. [less ▲] Detailed reference viewed: 133 (13 UL)Phase diagram of spin-1 chains with Dzyaloshinskii-Moriya interaction ; ; et al in Physical Review. B (2019), 100 We investigate an antiferromagnetic spin-1 Heisenberg chain in the presence of Dyzaloshinskii-Moriya interactions (DMI) and an external magnetic field. We study the resulting spin chain using a ... [more ▼] We investigate an antiferromagnetic spin-1 Heisenberg chain in the presence of Dyzaloshinskii-Moriya interactions (DMI) and an external magnetic field. We study the resulting spin chain using a combination of numerical and analytical techniques. Using DMRG simulations to determine the spectral gap and the entanglement spectrum, we map out the phase diagram as a function of magnetic field strength and DMI strength. We provide a qualitative interpretation for these numerical findings by mapping the spin-1 chain on a spin-1/2 ladder and using a bosonization approach. [less ▲] Detailed reference viewed: 25 (1 UL)Z4 parafermions in one-dimensional fermionic lattices Calzona, Alessio ; ; et al in Physical Review. B, Condensed Matter (2018), 98 Parafermions are emergent excitations which generalize Majorana fermions and are potentially relevant to topological quantum computation. Using the concept of Fock parafermions, we present a mapping ... [more ▼] Parafermions are emergent excitations which generalize Majorana fermions and are potentially relevant to topological quantum computation. Using the concept of Fock parafermions, we present a mapping between lattice Z4-parafermions and lattice spin-1/2 fermions which preserves the locality of operators with Z4 symmetry. Based on this mapping, we construct an exactly solvable, local one-dimensional fermionic Hamiltonian which hosts parafermionic edge states. We numerically show that the parafermionic phase remains stable in a wide range of parameters, and discuss its signatures in the fermionic spectral function. [less ▲] Detailed reference viewed: 101 (1 UL)Fundamental limits to helical edge conductivity due to sphin-phonon scattering Groenendijk, Solofo ; ; Schmidt, Thomas in Physical Review. B, Condensed Matter (2018), 97 Detailed reference viewed: 102 (11 UL)Universal scaling of quench-induced correlations in a one-dimensional channel at finite temperature Calzona, Alessio ; ; et al in SciPost Physics (2018) It has been shown that a quantum quench of interactions in a one-dimensional fermion system at zero temperature induces a universal power law ∝t−2 in its long-time dynamics. In this paper we demonstrate ... [more ▼] It has been shown that a quantum quench of interactions in a one-dimensional fermion system at zero temperature induces a universal power law ∝t−2 in its long-time dynamics. In this paper we demonstrate that this behaviour is robust even in the presence of thermal effects. The system is initially prepared in a thermal state, then at a given time the bath is disconnected and the interaction strength is suddenly quenched. The corresponding effects on the long times dynamics of the non-equilibrium fermionic spectral function are considered. We show that the non-universal power laws, present at zero temperature, acquire an exponential decay due to thermal effects and are washed out at long times, while the universal behaviour ∝t−2 is always present. To verify our findings, we argue that these features are also visible in transport properties at finite temperature. The long-time dynamics of the current injected from a biased probe exhibits the same universal power law relaxation, in sharp contrast with the non-quenched case which features a fast exponential decay of the current towards its steady value, and thus represents a fingerprint of quench-induced dynamics. Finally, we show that a proper tuning of the probe temperature, compared to that of the one-dimensional channel, can enhance the visibility of the universal power-law behaviour. [less ▲] Detailed reference viewed: 123 (1 UL)Fermionic reaction coordinates and their application to an autonomous Maxwell demon in the strong-coupling regime ; ; Schmidt, Thomas et al in Physical Review B (2018), 97(20), Detailed reference viewed: 157 (6 UL) |
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