Mini-symposium: Quantum transport of charge and heat

Mini-symposium in connection with the PhD defense of Simon Wozny, with one local speaker and two members of Simons committee. The schedule is (full abstracts below): 

09:30 - 10:10 - Adam Burke, Experimental aspects of QD thermoelectrics
10:10 - 10:50 - Björn Sothmann, Quantized phase-coherent heat transport of counterpropagating Majorana modes
10:50 - 11:10 - break and coffee
11:10 - 11:50 - Jonas Fransson, The chiral induced spin selectivity effect – dissipation and breaking the chiral symmetry 

Adam Burke (Lund University)

Title: Experimental aspects of QD thermoelectrics

Abstract:

I will present a select overview of our experimental activities in nanowire-based QD thermoelectrics. I will then also present our initial approaches at measuring thermal gradient induced fluctuations in our nanowire based QD heat engines, and touch upon the challenges and perspectives of measuring noise toward testing TURs.

Björn Sothmann (Universität Duisburg-Essen)

Title: Quantized phase-coherent heat transport of counterpropagating Majorana modes

Abstract:

Majorana modes have received considerable interest for their potential use as fault-tolerant qubits in topological quantum computing. However, probing the existence of Majorana modes is challenging as they are charge neutral and have zero energy. In this talk, we demonstrate that phase-coherent heat transport constitutes a powerful tool to probe Majorana physics in topological Josephson junctions. We predict that the thermal conductance transverse to the direction of the superconducting phase bias is universally quantized by half the thermal conductance quantum at phase difference phi=pi. This behavior is in direct contrast to the thermal conductance of a trivial Josephson junction which is suppressed at any phase difference phi. Thus, thermal transport can provide strong evidence for the existence of Majorana modes in topological Josephson junctions.

[1] A. G. Bauer, B. Scharf, L. W. Molenkamp, E. M. Hankiewicz, B. Sothmann, Phys. Rev. B 104, L201410 (2021).

Jonas Fransson (Uppsala University)

Title: The chiral induced spin selectivity effect – dissipation and breaking the chiral symmetry

Abstract:

The chiral induced spin selectivity (CISS) effect originates from structural chirality and offers a route to provide strongly spin-polarized currents and localized magnetic moments, based on organic molecules only without incorporation of magnetic elements or metals. While there are numerous reproductions of the result experimentally, the theoretical understanding is yet based on effective modeling where various origins of the effect have been suggested. It is, however, indisputable that chirality and spin-orbit coupling are connected. For the emergence of spin-dependent effects, time-reversal symmetry has to be broken and I will discuss possible, viable, and realistic mechanisms that break time-reversal symmetry. Moreover, using a simple effective model for a generic set-up pertaining to transport measurements of the CISS effect, several features observed in experiments can be explained.