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Light, the universe, and everything -- 12 Herculean tasks for quantum cowboys and black diamond skiers
Authors:
Girish Agarwal,
Roland Allen,
Iva Bezdekova,
Robert Boyd,
Goong Chen,
Ronald Hanson,
Dean Hawthorne,
Philip Hemmer,
Moochan Kim,
Olga Kocharovskaya,
David Lee,
Sebastian Lidstrom,
Suzy Lidstrom,
Harald Losert,
Helmut Maier,
John Neuberger,
Miles Padgett,
Mark Raizen,
Surjeet Rajendran,
Ernst Rasel,
Wolfgang Schleich,
Marlan Scully,
Gavriil Shchedrin,
Gennady Shvets,
Alexei Sokolov
, et al. (7 additional authors not shown)
Abstract:
The Winter Colloquium on the Physics of Quantum Electronics (PQE) has been a seminal force in quantum optics and related areas since 1971. It is rather mindboggling to recognize how the concepts presented at these conferences have transformed scientific understanding and human society. In January, 2017, the participants of PQE were asked to consider the equally important prospects for the future,…
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The Winter Colloquium on the Physics of Quantum Electronics (PQE) has been a seminal force in quantum optics and related areas since 1971. It is rather mindboggling to recognize how the concepts presented at these conferences have transformed scientific understanding and human society. In January, 2017, the participants of PQE were asked to consider the equally important prospects for the future, and to formulate a set of questions representing some of the greatest aspirations in this broad field. The result is this multi-authored paper, in which many of the world's leading experts address the following fundamental questions: (1) What is the future of gravitational wave astronomy? (2) Are there new quantum phases of matter away from equilibrium that can be found and exploited - such as the time crystal? (3) Quantum theory in uncharted territory: What can we learn? (4) What are the ultimate limits for laser photon energies? (5) What are the ultimate limits to temporal, spatial, and optical resolution? (6) What novel roles will atoms play in technology? (7) What applications lie ahead for nitrogen-vacancy centers in diamond? (8) What is the future of quantum coherence, squeezing, and entanglement for enhanced superresolution and sensing? (9) How can we solve (some of) humanity's biggest problems through new quantum technologies? (10) What new understanding of materials and biological molecules will result from their dynamical characterization with free electron lasers? (11) What new technologies and fundamental discoveries might quantum optics achieve by the end of this century? (12) What novel topological structures can be created and employed in quantum optics?
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Submitted 16 February, 2018;
originally announced February 2018.
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Ballistic geometric resistance resonances in a single surface of a topological insulator
Authors:
Hubert Maier,
Johannes Ziegler,
Ralf Fischer,
Dmitriy Kozlov,
Ze Don Kvon,
Nikolay Mikhailov,
Sergey A. Dvoretsky,
Dieter Weiss
Abstract:
Transport in topological matter has shown a variety of novel phenomena over the last decade. Although numerous transport studies have been conducted on three-dimensional topological insulators (3D-TIs), study of ballistic motion and thus exploration of potential landscapes on a hundred nanometer scale is for the prevalent TI materials almost impossible due to their low carrier mobility. Therefore…
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Transport in topological matter has shown a variety of novel phenomena over the last decade. Although numerous transport studies have been conducted on three-dimensional topological insulators (3D-TIs), study of ballistic motion and thus exploration of potential landscapes on a hundred nanometer scale is for the prevalent TI materials almost impossible due to their low carrier mobility. Therefore it is unknown whether helical Dirac electrons in TIs, bound to interfaces between topologically distinct materials, can be manipulated on the nanometer scale by local gates or locally etched regions. Here we impose a submicron periodic potential onto a single surface of Dirac electrons in high mobility strained mercury telluride (HgTe), which is a strong TI. Pronounced geometric resistance resonances constitute the first observation of a ballistic effect in 3D-TIs.
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Submitted 25 August, 2017;
originally announced August 2017.
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Probing Spin Helical Surface States in Topological HgTe Nanowires
Authors:
Johannes Ziegler,
Raphael Kozlovsky,
Cosimo Gorini,
Ming-Hao Liu,
Sabine Weishäupl,
Hubert Maier,
Ralf Fischer,
Dmitriy A. Kozlov,
Ze Don Kvon,
Nikolay N. Mikhailov,
Sergey A. Dvoretsky,
Klaus Richter,
Dieter Weiss
Abstract:
Nanowires with helical surface states represent key prerequisites for observing and exploiting phase-coherent topological conductance phenomena, such as spin-momentum locked quantum transport or topological superconductivity. We demonstrate in a joint experimental and theoretical study that gated nanowires fabricated from high-mobility strained HgTe, known as a bulk topological insulator, indeed p…
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Nanowires with helical surface states represent key prerequisites for observing and exploiting phase-coherent topological conductance phenomena, such as spin-momentum locked quantum transport or topological superconductivity. We demonstrate in a joint experimental and theoretical study that gated nanowires fabricated from high-mobility strained HgTe, known as a bulk topological insulator, indeed preserve the topological nature of the surface states, that moreover extend phase-coherently across the entire wire geometry. The phase-coherence lengths are enhanced up to 5 $μ$m when tuning the wires into the bulk gap, so as to single out topological transport. The nanowires exhibit distinct conductance oscillations, both as a function of the flux due to an axial magnetic field, and of a gate voltage. The observed $h/e$-periodic Aharonov-Bohm-type modulations indicate surface-mediated quasi-ballistic transport. Furthermore, an in-depth analysis of the scaling of the observed gate-dependent conductance oscillations reveals the topological nature of these surface states. To this end we combined numerical tight-binding calculations of the quantum magneto-conductance with simulations of the electrostatics, accounting for the gate-induced inhomogenous charge carrier densities around the wires. We find that helical transport prevails even for strongly inhomogenous gating and is governed by flux-sensitive high-angular momentum surface states that extend around the entire wire circumference.
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Submitted 11 December, 2017; v1 submitted 23 August, 2017;
originally announced August 2017.