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Quantum coherence, quantum statistics, and superconductivity in mesoscopic systems

Applicant Bruder Christoph
Number 126637
Funding scheme Project funding (Div. I-III)
Research institution Departement Physik Universität Basel
Institution of higher education University of Basel - BS
Main discipline Theoretical Physics
Start/End 01.10.2009 - 30.09.2011
Approved amount 313'109.00
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Keywords (8)

condensed-matter theory; quantum coherence; nanomechanics; ultracold atoms; mesoscopic superconductivity; ; noise and full counting statistics;

Lay Summary (English)

Lead
Lay summary
The physics of mesoscopic systems, i.e., electronic structures in the nanometer range, is one of the most active research areas of condensed-matter physics. These systems allow us to study fundamental physics questions, and their understanding is a necessary prerequisite for possible future electronic device applications. The goal of our research is to exploit and analyze quantum interference effects in such electronic circuits. In the last couple of years, new exciting areas have opened up, like nanomechanics, or the interface of ultracold atoms and condensed-matter systems.In particular, our group (about 2 PhD students and 3 Postdocs) plans to study the interplay of electric currents through nanostructures with mechanical degrees of freedom (nanomechanics). We are also interested in fluctuation and noise phenomena: electrical currents are not exactly constant but fluctuate, and these fluctuations contain a great deal of information about the quantum nature of the electrons that carry the current. We will also investigate ultracold atoms which can be used to study quantum coherence and quantum many-body phenomena. Cold atoms can be trapped in so-called optical lattices and show similarities to electrons in a crystal lattice. The great advantage of cold atoms is that the properties of the lattice can be controlled much more easily than in the case of a crystal lattice. Finally, we are also interested in the foundations of quantum mechanics (entanglement, weak measurements in solid-state systems).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Interferometric and noise signatures of Majorana fermion edge states in transport experiments
Strübi G, Belzig W, Choi M-S, Bruder C (2011), Interferometric and noise signatures of Majorana fermion edge states in transport experiments, in Physical Review Letters, 107(13), 136403-136403.
Controlling qubit arrays with anisotropic XXZ Heisenberg interaction by acting on a single qubit
Heule R, Bruder C, Burgarth D, Stojanovic VM (2011), Controlling qubit arrays with anisotropic XXZ Heisenberg interaction by acting on a single qubit, in EUROPEAN PHYSICAL JOURNAL D, 63(1), 41-46.
Ideal quantum nondemolition measurement of a flux qubit at variable bias
Wang YD, Zhu XB, Bruder C (2011), Ideal quantum nondemolition measurement of a flux qubit at variable bias, in PHYSICAL REVIEW B, 83(13), 134504-134504.
Effects of a single fermion in a Bose Josephson junction
Rinck M, Bruder C (2011), Effects of a single fermion in a Bose Josephson junction, in PHYSICAL REVIEW A, 83(2), 023608-023608.
Local quantum control of Heisenberg spin chains
Heule R, Bruder C, Burgarth D, Stojanovic VM (2010), Local quantum control of Heisenberg spin chains, in PHYSICAL REVIEW A, 82(5), 052333-052333.
Greenberger-Horne-Zeilinger generation protocol for N superconducting transmon qubits capacitively coupled to a quantum bus
Aldana S, Wang Y-D, Bruder C (2010), Greenberger-Horne-Zeilinger generation protocol for N superconducting transmon qubits capacitively coupled to a quantum bus, in Physical Review B - Condensed Matter and Materials Physics, 84(13), 134519-134519.
Polaronic signatures and spectral properties of graphene antidot lattices
Stojanovic VM, Vukmirovic N, Bruder C (2010), Polaronic signatures and spectral properties of graphene antidot lattices, in PHYSICAL REVIEW B, 82(16), 165410-165410.
Detection of Qubit-Oscillator Entanglement in Nanoelectromechanical Systems
Schmidt TL, Borkje K, Bruder C, Trauzettel B (2010), Detection of Qubit-Oscillator Entanglement in Nanoelectromechanical Systems, in PHYSICAL REVIEW LETTERS, 104(17), 177205-177205.
One-step multiqubit Greenberger-Horne-Zeilinger state generation in a circuit QED system
Wang YD, Chesi S, Loss D, Bruder C (2010), One-step multiqubit Greenberger-Horne-Zeilinger state generation in a circuit QED system, in PHYSICAL REVIEW B, 81(10), 104524-104524.
Electron-phonon coupling in graphene antidot lattices: An indication of polaronic behavior
Vukmirovic Nenad, Stojanovic Vladimir M., Vanevic Mihajlo (2010), Electron-phonon coupling in graphene antidot lattices: An indication of polaronic behavior, in PHYSICAL REVIEW B, 81(4), 041408-041408.
Interplay of the Aharonov-Bohm effect and Klein tunneling in graphene
Schelter Joerg, Bohr Dan, Trauzettel Bjoern (2010), Interplay of the Aharonov-Bohm effect and Klein tunneling in graphene, in PHYSICAL REVIEW B, 81(19), 195411-195411.
Quantum transport through single-molecule junctions with orbital degeneracies
Schultz Maximilian G. (2010), Quantum transport through single-molecule junctions with orbital degeneracies, in PHYSICAL REVIEW B, 82(15), 155408-155408.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Workshop in Electronic Correlations in Models and Materials 14.09.2011 Augsburg, Deutschland
Frontiers of Quantum and Mesoscopic Thermodynamics 24.07.2011 Prague, Czech Republic
Swiss-Swedish Meeting on Quantum Materials and Devices 09.01.2011 Les Diablerets, Schweiz
KITP Workshop Beyond Standard Optical Lattices 01.11.2010 Santa Barbara, USA
Ruperto-Carola-Symposium on Hybrid Quantum Systems 13.05.2010 Heidelberg, Deutschland
Gordon Conference on Mechanical systems in the quantum regime 21.03.2010 Galveston, USA


Self-organised

Title Date Place
Workshop on "Atomic physics using superconducting qubits" 16.05.2011 Beijing, China

Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions Geheimnisvolle Quantenwelt German-speaking Switzerland 17.04.2010

Associated projects

Number Title Start Funding scheme
137551 Quantum coherence, quantum statistics, and superconductivity in mesoscopic systems 01.10.2011 Project funding (Div. I-III)
155933 Quantum coherence, quantum statistics, and superconductivity in mesoscopic systems 01.10.2014 Project funding (Div. I-III)
117603 Quantum coherence, quantum statistics, and superconductivity in mesoscopic systems 01.10.2007 Project funding (Div. I-III)

Abstract

We want to generalize current theoretical models of quantum point contact (QPC) position detectors in nanomechanical systems by considering a scattering theory of the QPC where tunneling is no longer assumed to be small. We plan to investigate the possibility of generating entanglement between two nanomechanical oscillators by simultaneous measurement of the position of the two oscillators by a single tunnel junction. We will study the perspectives of a suspended nanomechanical device as a detector of frequency-dependent quantum noise. We will study the dynamics of ultra-cold atoms in optical superlattices and the entanglement in such multipartite systems. We will also investigate the single-atom staircase for double-well lattices containing a mixture of bosonic and fermionic atoms. We will study the weak measurement theory of solid-state qubits. We will investigate the onset of the Josephson effect between two fermionic reservoirs (superconductors/superfluids) using a number-conserving theory. We will investigate current cross-correlations in a superconducting beam splitter if the superconductor is characterized by a non-trivial state.
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