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Theory of solid-state devices for quantum computation and communication

English title Theory of solid-state devices for quantum computation and communication
Applicant Burkard Guido
Number 106310
Funding scheme SNSF Professorships
Research institution Universität Konstanz
Institution of higher education University of Basel - BS
Main discipline Theoretical Physics
Start/End 01.07.2005 - 30.06.2009
Approved amount 633'671.00
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All Disciplines (2)

Theoretical Physics
Condensed Matter Physics

Keywords (6)

quantum computing; quantum information; condensed matter; mesoscopic transport; semiconductor optics; spintronics

Lay Summary (English)

Lay summary
The objective of this research project is to gain theoreticalunderstanding of quantum coherence, decoherence (loss of coherence), andthe potential use for quantum information processing (QIP) of solid-statedevices on the nano- and micrometer scale. We are focused on (A) SCqubits, i.e., quantum coherence in mesoscopic superconducting (SC) devicesand their use for quantum computing (QC), (B) solid-state emitters ofentangled photons for quantum communication (QCC), and (C) the theory ofQIP, in particular quantum error correction and fault-tolerant QC. We aimat problems posed by current and imminent experimental work. Its intent isboth to enable scientific progress in the implementation of solid-stateQIP and to increase our understanding of the foundations of quantummechanics under the new aspect of quantum information theory. It can alsobe expected that new insights into condensed matter, materials, and devicephysics for the involved systems will be gained from our research.It has been realized already in the 1970s that the concepts of informationand computation can only be truly understood on a physical level, that“Information is physical” (Landauer). The emerging field of QC and QIP hasdemonstrated even more strikingly that the computational power of a devicedepends on its physical realization. The discoveries of efficient quantumalgorithms for problems that appear to be intrinsically hard for classicalcomputers, prime factoring (Shor), database search (Grover), etc., haveprovided strong evidence for an exponential gap between the computationalcapabilities of classical and quantum hardware, thus providing a strongincentive for the study of devices for QIP. The discoveries of quantum keydistribution for cryptography, quantum teleportation, and other, new QCCprotocols have further established the fundamental and qualitativedifference between classical and quantum information.Solid-state proposals have a large potential for QIP because of theirscalability. Two of the most promising candidates are (1) superconducting(SC) circuits and (2) spin-based qubits in semiconductor nano-structures.We focus on macroscopic quantum properties of SC devices, which havealready led to impressive experimental results, and on the main challengefor their further development, the decoherence and visibility problems.While SC devices are among the leading proposals for scalable solid-statequbits and have the advantage of relatively easy controllability andread-out, their macroscopic nature is also a major challenge due toexternal noise causing decoherence.see also:
Direct link to Lay Summary Last update: 21.02.2013

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