We study the electronic thermal drag in two different Coulomb-coupled systems, the first one composed of two Coulomb blockaded metallic islands and the second one consisting of two parallel quantum wires. The two conductors of each system are electrically isolated and placed in the two circuits (the drive and the drag) of a four-electrode setup. The systems are biased, either by a temperature ∆T or a voltage V difference, on the drive circuit, while no biases are present on the drag circuit. In the case of a pair of metallic islands we use a master equation approach to determine the general properties of the dragged heat current I (h) drag , accounting also for co-tunneling contributions and the presence of large biases. Analytic results are obtained in the sequential tunneling regime for small biases, finding, in particular, that I (h) drag is quadratic in ∆T or V and nonmonotonous as a function of the inter-island coupling. Finally, by replacing one of the electrodes in the drag circuit with a superconductor, we find that heat can be extracted from the other normal electrode. In the case of the two interacting quantum wires, using the Luttinger liquid theory and the bosonization technique, we derive an analytic expression for the thermal trans-resistivity ρ (h) 12 , in the weak-coupling limit and at low temperatures. ρ (h) 12 turns out to be proportional to the electrical trans-resistivity, in such a way that their ratio (a kind of Wiedemann-Franz law) is proportional to T 3 . We find that ρ (h) 12 is proportional to T for low temperatures and decreases like 1/T for intermediate temperatures or like 1/T 3 for high temperatures. We complete our analyses by performing numerical simulations that confirm the above results and allow to access the strong coupling regime. arXiv:1802.10322v2 [cond-mat.mes-hall]

Recent experiments on K3C60 and layered copper-oxide materials have reported substantial changes in the optical response following application of an intense THz pulse. These data have been interpreted as the stimulation of a transient superconducting state even at temperatures well above the equilibrium transition temperature. We propose an alternative phenomenology based on the assumption that the pulse creates a non-superconducting, though non-equilibrium situation in which the linear response conductivity is negative. The negative conductivity implies that the spatially uniform pre-pulse state is unstable and evolves to a new state with a spontaneous electric polarization. This state exhibits coupled oscillations of entropy and electric charge whose coupling to incident probe radiation modifies the reflectivity, leading to an apparently superconducting-like response that resembles the data. Dependencies of the reflectivity on polarization and angle of incidence of the probe are predicted and other experimental consequences are discussed.There has been substantial interest in the use of intense radiation fields to drive materials into non-equilibrium states [1]. Particular excitement has been generated by reports [2-4] of dramatic changes in the electromagnetic response of K 3 C 60 and layered copper-oxide materials after their exposure to intense THz radiation. The key features of the data are: i) before the application of the pump pulse, the material is in the normal (unbroken symmetry) state; ii) after photo-excitation of the material by the pump, the reflectivity R(ω) is measured as a function of the frequency ω of a probe field; iii) for some time after the pump excitation, R(ω) is found to be substantially enhanced at low frequency, see the insets in Fig. 1. This enhancement has been interpreted in terms of the creation, by the pulse, of a superconducting (SC) state.Theories proposed to date [5][6][7][8][9][10][11] are all based on the premise that the pump pulse changes the interactions and/or structure in a way that enables a transition to a broken symmetry SC state at a temperature much higher than that of the equilibrium transition. In this work we point out that the data do not require this interpretation; instead the observations can be understood within a general phenomenology that does not involve SC.The essence of our model is: i) we argue on general grounds that a non-equilibrium system can exhibit a negative linear response conductivity; ii) in this case the spatially homogeneous state is unstable and evolves to a new state characterized by domains of constant electric field bounded by sheets of charge, Fig. 2a; iii) in the experimentally relevant situation where the non-equilibrium state is produced by a pulse and thereafter evolves with a conserved energy, we show that the system sustains collective modes strongly coupled to incident radiation, leading to the reflectivity curves shown in Fig. 1. i) Consider the system out of equilibrium. The sample occupies the half space z > 0. Pump radiatio...

Quantum systems evolving unitarily and subject to quantum measurements exhibit various types of non-equilibrium phase transitions, arising from the competition between unitary evolution and measurements. Dissipative phase transitions in steady states of time-independent Liouvillians and measurement induced phase transitions at the level of quantum trajectories are two primary examples of such transitions. Investigating a many-body spin system subject to periodic resetting measurements, we argue that many-body dissipative Floquet dynamics provides a natural framework to analyze both types of transitions. We show that a dissipative phase transition between a ferromagnetic ordered phase and a paramagnetic disordered phase emerges for long-range systems as a function of measurement probabilities. A measurement induced transition of the entanglement entropy between volume law scaling and sub-volume law scaling is also present, and is distinct from the ordering transition. The two phases correspond to an error-correcting and a quantum-Zeno regimes, respectively. The ferromagnetic phase is lost for short range interactions, while the volume law phase of the entanglement is enhanced. An analysis of multifractal properties of wave function in Hilbert space provides a common perspective on both types of transitions in the system. Our findings are immediately relevant to trapped ion experiments, for which we detail a blueprint proposal based on currently available platforms.

The 4d transition metal perovskites Can+1RunO3n+1 have attracted interest for their strongly interacting electronic phases showing pronounced sensitivity to controllable stimuli like strain, temperature, and even electrical current. Through multi-messenger low-temperature nano-imaging, we reveal a spontaneous striped texture of coexisting insulating and metallic domains in single crystals of the bilayer ruthenate Ca3(TixRu1-x)2O7 across its first-order Mott transition at $$T \approx 95$$ T ≈ 95 K. We image on-demand anisotropic nucleation and growth of these domains under in situ applied uniaxial strain rationalized through control of a spontaneous Jahn-Teller distortion. Our scanning nano-susceptibility imaging resolves the detailed susceptibility of coexisting phases to strain and temperature at the transition threshold. Comparing these nano-imaging results to bulk-sensitive elastoresistance measurements, we uncover an emergent “domain susceptibility” sensitive to both the volumetric phase fractions and elasticity of the self-organized domain lattice. Our combined susceptibility probes afford nano-scale insights into strain-mediated control over the insulator-metal transition in 4d transition metal oxides.