Quantum System Theory Research Team

Principal Investigator

PI Name Daniel Loss
Degree Ph.D.
Title Team Leader
Brief Resume
1985Ph.D. in Theoretical Physics, University of Zurich, Switzerland
1985Postdoctoral Research Associate, University of Zurich, Switzerland
1989Postdoctoral Research Fellow, University of Illinois at Urbana-Champaign, USA
1991Research Scientist, IBM T. J. Watson Research Center, USA
1993Assistant/Associate Professor, Simon Fraser University, Canada
1996Professor, Department of Physics, University of Basel, Switzerland (-present)
2012Team Leader, Emergent Quantum System Research Team, RIKEN
2013Team Leader, Quantum System Theory Research Team, Quantum Information Electronics Division, RIKEN Center for Emergent Matter Science (-present)

Outline

Our team is working on the quantum theory of condensed matter with a focus on spin and phase coherent phenomena in semiconducting and magnetic nanostructures. In particular, the team investigates the fundamental principles of quantum information processing in the solid state with a focus on spin qubits in quantum dots, superconducting qubits, and topological quantum states such as Majorana fermions and parafermions. This involves the study of decoherence in many-body systems and scalable quantum computing technologies based on surface codes and long-distance entanglement schemes. We also study nuclear spin phases, many-body effects in low-dimensional systems, quantum Hall effect, topological matter, spin orbit interaction, and quantum transport of magnetization.

Research Fields

Theoretical Physics, Quantum Theory of Condensed Matter

Keywords

Quantum dots
Spin-based quantum information science
RKKY interaction in low dimensions
Topological quantum matters
Majorana fermions and parafermions

Results

Topological Floquet Phases in Driven Coupled Rashba Nanowires

Even though the most of the recent studies of topological matter were focused on static structures, it has been recently proposed to extend the investigations to non-equilibrium systems. We circumvent the difficulty of analysis of a two-dimensional system with electron-electron interactions by considering a strongly anisotropic 2D system formed by weakly coupled Rashba wires (see the figure), where each of them can be treated as a one-dimensional Luttinger liquid by bosonization. This allowed us to introduce the Floquet version not only of topological insulators but also of Weyl semimetals in driven 2D systems. Importantly, in this way we can also address fractional regimes and are able to obtain the Floquet version of fractional TIs and Weyl semimetals.

Upper panel: An array of quantum wires under a time dependent driving realizing the Floquet topological insulator.
Lower panel: The phase diagram of the model shown in the upper panel as a function of the Floquet coupling tF and the tunneling amplitude t2.
J. Klinovaja, P. Stano, D. Loss, “Topological Floquet Phases in Driven Coupled Rashba Nanowires”, Phys. Rev. Lett. 116, 176401 (2016) © APS

Members

Daniel Loss

Team Leader loss.daniel[at]riken.jp R

Peter Stano

Senior Research Scientist peter.stano[at]riken.jp

Chen-Hsuan Hsu

Postdoctoral Researcher chen-hsuan.hsu[at]riken.jp

Pasquale Marra

Postdoctoral Researcher

お問い合わせ

2-1 Hirosawa, Wako, Saitama 351-0198 Japan

E-mail:
loss.daniel[at]riken.jp

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