Nonequilibrium electron spectroscopy of Luttinger liquids

Understanding the effects of nonequilibrium on strongly interacting quantum systems is a challenging problem in condensed matter physics. In dimensions greater than one, interacting electrons can often be understood within Fermi-liquid theory where low-energy excitations are weakly interacting quasiparticles. On the contrary, electrons in one dimension are known to form a strongly-correlated phase of matter called a Luttinger liquid (LL), whose low-energy excitations are collective density waves, or plasmons, of the electron gas. Here we show that spectroscopy of locally injected high-energy electrons can be used to probe energy relaxation in the presence of such strong correlations. For detection energies near the injection energy, the electron distribution is described by a power law whose exponent depends in a continuous way on the Luttinger parameter, and energy relaxation can be attributed to plasmon emission. For a chiral LL as realized at the edge of a fractional quantum Hall state, the distribution function grows linearly with the distance to the injection energy, independent of filling fraction.Comment: 4+ pages, 3 figure

Influence of topological excitations on Shapiro steps and microwave dynamical conductance in bilayer exciton condensates

The quantum Hall state at total filling factor $\nu_T=1$ in bilayer systems realizes an exciton condensate and exhibits a zero-bias tunneling anomaly, similar to the Josephson effect in the presence of fluctuations. In contrast to conventional Josephson junctions, no Fraunhofer diffraction pattern has been observed, due to disorder induced topological defects, so-called merons. We consider interlayer tunneling in the presence of microwave radiation, and find Shapiro steps in the tunneling current-voltage characteristic despite the presence of merons. Moreover, the Josephson oscillations can also be observed as resonant features in the microwave dynamical conductance

Massage for Combat Injuries in Veteran with Undisclosed PTSD: a Retrospective Case Report.

INTRODUCTION: Massage has shown promise in reducing symptoms related to dissociation and anxiety that can exacerbate chronic pain and suffering. The combat wounded, veteran population is increasing and requires a multidisciplinary approach for comprehensive treatment. This case study examines massage therapy use to improve veteran combat injury rehabilitation and recovery experience through purposive, retrospective, and comprehensive SOAP note review. METHODS: A 31-year-old White male received seven, 60-min, full body massages for combat related shoulder injury complications incurred approximately six years before presentation. The right shoulder sustained a broken humeral head and complete dislocation during a defensive maneuver in a life-threatening attack. This case study utilized data from three different assessments: goniometric measurements for shoulder range of motion, observation and documentation for environmental comfort behaviors, and client self-report for treatment goal attainment. Six weekly, full body, 60-min massages were completed sequentially. A follow-up 60-min treatment was completed at Week 8. Treatment to the injured area included focused trigger point therapy, myofascial release, and proprioceptive neuromuscular facilitation to the neck, shoulder, and chest. RESULTS: Total percent change for active flexion, extension, abduction, adduction, internal rotation, and external rotation were 12.5, 150, 40, 167, 14.3, and 0%, respectively. Total percent change for passive flexion, extension, abduction, adduction, internal rotation, and external rotation were 63.6, 350, 66.7, 450, 133, and 77.8%, respectively. Environmental comfort behaviors were reduced. Client treatment goals were attained. CONCLUSIONS: Massage therapy provided meaningful benefit to a combat injury for a veteran with PTSD

Unconventional pairing and electronic dimerization instabilities in the doped Kitaev-Heisenberg model

We study the quantum many-body instabilities of the $t -J_{\mathrm{K}} - J_{\mathrm{H}}$ Kitaev-Heisenberg Hamiltonian on the honeycomb lattice as a minimal model for a doped spin-orbit Mott insulator. This spin-$1/2$ model is believed to describe the magnetic properties of the layered transition-metal oxide Na$_2$IrO$_3$. We determine the ground-state of the system with finite charge-carrier density from the functional renormalization group (fRG) for correlated fermionic systems. To this end, we derive fRG flow-equations adapted to the lack of full spin-rotational invariance in the fermionic interactions, here represented by the highly frustrated and anisotropic Kitaev exchange term. Additionally employing a set of Ward identities for the Kitaev-Heisenberg model, the numerical solution of the flow equations suggests a rich phase diagram emerging upon doping charge carriers into the ground-state manifold ($\mathbb{Z}_2$ quantum spin liquids and magnetically ordered phases). We corroborate superconducting triplet $p$-wave instabilities driven by ferromagnetic exchange and various singlet pairing phases. For filling $\delta > 1/4$, the $p$-wave pairing gives rise to a topological state with protected Majorana edge-modes. For antiferromagnetic Kitaev and ferromagnetic Heisenberg exchange we obtain bond-order instabilities at van Hove filling supported by nesting and density-of-states enhancement, yielding dimerization patterns of the electronic degrees of freedom on the honeycomb lattice. Further, our flow equations are applicable to a wider class of model Hamiltonians.Comment: 24 pages, 18 figures, corresponds to journal versio

The Role of Interactions in an Electronic Fabry-Perot Interferometer Operating in the Quantum Hall Effect Regime

Interference of edge channels is expected to be a prominent tool for studying statistics of charged quasiparticles in the quantum Hall effect (QHE) [A. Stern (2008), Ann. Phys. 1:204; C. Chamon et al. (1997), Phys. Rev. B, 55:2331]. We present here a detailed study of an electronic Fabry-Perot interferometer (FPI) operating in the QHE regime [C. Chamon et al. (1997), Phys. Rev. B, 55:2331], with the phase of the interfering quasiparticles controlled by the Aharonov-Bohm (AB) effect. Our main finding is that Coulomb interactions among the electrons dominate the interference, even in a relatively large area FPI, leading to a strong dependence of the area enclosed by the interference loop on the magnetic field. In particular, for a composite edge structure, with a few independent edge channels propagating along the edge, interference of the outmost edge channel (belonging to the lowest Landau level) was insensitive to magnetic field; suggesting a constant enclosed flux. However, when any of the inner edge channels interfered, the enclosed flux decreased when the magnetic field increased. By intentionally varying the enclosed area with a biased metallic gate and observing the periodicity of the interference pattern, charges e (for integer filling factors) and e/3 (for a fractional filling factor) were found to be expelled from the FPI. Moreover, these observations provided also a novel way of detecting the charge of the interfering quasiparticles.Comment: 8 pages, 8 figure

Hot stuff: Research and policy principles for heat decarbonisation through smart electrification

This is the author accepted manuscript. The final version is available on open access from Elsevier via the DOI in this recordThere is a need for major greenhouse gas emission reductions from heating in order to meet global decarbonisation goals. Electricity is expected to meet much of the heat demand currently provided by fossil fuels in the future and heat pumps may have an important role. This electrification transformation is not without challenges. Through a detailed narrative review alongside expert elicitation, we propose four principles for heat decarbonisation via electrification: putting energy efficiency first, valuing heat as a flexible load, understanding the emission impacts of heat electrification and designing electricity tariffs to reward flexibility. As a route to heat decarbonisation, when combined, these principles can offer significant consumer and carbon reduction benefits. In the short term these principles can encourage the smooth integration of heat electrification and in the longer term these principles are expected to reduce the scale of required infrastructural expansion. We propose a number of policy mechanisms which can be used to support these principles including (building) regulation, financial support, carbon standards, energy efficiency obligations and pricing.Engineering and Physical Sciences Research Council (EPSRC

Incoherent scatterer in a Luttinger liquid: a new paradigmatic limit

We address the problem of a Luttinger liquid with a scatterer that allows for both coherent and incoherent scattering channels. The asymptotic behavior at zero temperature is governed by a new stable fixed point: a Goldstone mode dominates the low energy dynamics, leading to a universal behavior. This limit is marked by equal probabilities for forward and backward scattering. Notwithstanding this non-trivial scattering pattern, we find that the shot noise as well as zero cross-current correlations vanish. We thus present a paradigmatic picture of an impurity in the Luttinger model, alternative to the Kane-Fisher picture.Comment: published version, 4 + epsilon pages, 1 figur

Scanning Gate Spectroscopy of transport across a Quantum Hall Nano-Island

We explore transport across an ultra-small Quantum Hall Island (QHI) formed by closed quan- tum Hall edge states and connected to propagating edge channels through tunnel barriers. Scanning gate microscopy and scanning gate spectroscopy are used to first localize and then study a single QHI near a quantum point contact. The presence of Coulomb diamonds in the spectroscopy con- firms that Coulomb blockade governs transport across the QHI. Varying the microscope tip bias as well as current bias across the device, we uncover the QHI discrete energy spectrum arising from electronic confinement and we extract estimates of the gradient of the confining potential and of the edge state velocity.Comment: 13 pages, 3 figure

Partition Functions of Non-Abelian Quantum Hall States

Partition functions of edge excitations are obtained for non-Abelian Hall states in the second Landau level, such as the anti-Read-Rezayi state, the Bonderson-Slingerland hierarchy and the Wen non-Abelian fluid, as well as for the non-Abelian spin-singlet state. The derivation is straightforward and unique starting from the non-Abelian conformal field theory data and solving the modular invariance conditions. The partition functions provide a complete account of the excitation spectrum and are used to describe experiments of Coulomb blockade and thermopower.Comment: 42 pages, 3 figures; published version; minor corrections to sect. 4.