Transcript Physics 795: Condensed Matter Theory

Physics 795:
Condensed Matter Theory
Ralf Bundschuh
Jason Ho
C. Jayaprakash
Julia Meyer
Bruce Patton
Bill Putikka
Mohit Randeria
Will Saam
David Stroud
Nandini Trivedi
John Wilkins
Physics 795: CMT - Nov 3, 2006
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Condensed Matter Theorists @ OSU
R. Bundschuh
W. Putikka
J. Ho
M. Randeria
C. Jayaprakash
W. Saam
J. Meyer
B. Patton
D. Stroud
N. Trivedi
& J. Wilkins
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Julia Meyer
Mesoscopic physics
[ meso = somewhere in between micro & macro ]
Interactions and disorder
in low-dimensional & nanostructured systems
CURRENT PROJECTS:
- deviations from one-dimensionality
in interacting quantum wires
- ultracold dipolar gases in optical lattices
- proximity effect in
superconductor-ferromagnet
hybrid structures
MY GROUP: 1 graduate student [ possibly one more opening ! ]
+ looking for one postdoc
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Bill Putikka Research Interests
Pairing Correlations for Models of
Strongly Correlated Electrons
●
High temperature expansions for the 2D
t-J, Hubbard Models (High Tc)
●
●
Superconducting correlation length
Currently no funding, but maybe by
spring (grants submitted this fall)
●
WO Putikka & MU Luchini PRL 96, 247001
(1996)
●
Spin Lifetimes in Semiconductors
Relaxation of nonequilibrium spin
distributions by a range of physical
processes
● Relevant for Spintronics
● Maybe relevant for Quantum Computing
• Currently supporting one grad student, Nick
Harmon
● WO Putikka & R Joynt PRB70, 113201
(2004)
●
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Mohit Randeria
Strongly interacting
Quantum many-body systems
• Superconductivity in doped Mott insulators
- High Tc superconductors
• Angle-resolved photoemission spectroscopy of
complex materials
• Cold atoms: superfluidity & BCS-BEC crossover
Group members: Rajdeep Sensarma (PhD student)
Roberto Diener (Post-doctoralPhysics
research
associate)
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DAVID STROUD: RESEARCH INTERESTS
• HIGH-Tc
SUPERCONDUCTORS.
•
We are studying electronic
properties of these materials.
QUBITS. We try to invent
controllable two-level
systems out of
superconductors, for
``quantum computing.’’
• NANOSCALE OPTICAL
MATERIALS. Tiny metal
grains in air or glass (or
linked together with strands
of DNA) have unique optical
properties, and aggregate at
low temperatures
Linke
r
DNA
• More information at
/~stroud/Research.html
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Nandini Trivedi
BIG PICTURE
Condensed Matter Theory
How do many electrons organise themselves?
The magic of quantum mechanics and statistical mechanics!
NEW PHASES AND
QUANTUM PHASE TRANSITIONS
Some of the most challenging problems in
condensed matter today deal with new phases
of matter generated by strong interactions
between the constituents. Disorder in such
correlated systems can produce novel effects.
Techniques: semianalytical; Quantum Monte Carlo techniques
matlab; mathematica
My Group:
Grad Students:
Kohjiro Kobayashi- Metal Insulator transition
Rajdeep SenSarma – High Tc Superconductivity
(jointly with M. Randeria)
Vamsi Akkineni – BCS-BEC Crossover in Ultracold Atoms
(jointly with D. Ceperley, Urbana)
Undergraduates:
Tim Arnold– Nano Superconductors
Eric Wolf– Dynamics of quantum systems
Group meetings:
every Friday at noon
E-mail ME IF YOU ARE
INTERESTED
Opening for at least
1 grad student
Other collaborations on Superconductor-Insulator Transition (Berkeley);
Optical Lattices (ISSP, Tokyo and Trento, Italy)
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John Wilkins
1. Predicting bandgap offsets of semiconductor heterostructures. The aim is to provide
predictive data for scientists and engineers designing new semiconductor devices.
Currently there is lot of trial and error (called combinatorial synthesis) to find desired band
gaps and the offset of valence and conduction bands. Current method are seldom better
than a factor of two (useless!).
2. Predicting defect formation and evolution in semiconductors and metals. Today we
have simple pictures that we believe are quantitative for motion of small interstitial clusters
in silicon and alpha->omega phase transition in titanium. Interest in the first is to eventually
understand how large defects are formed. [Generally these are undesirable. Knowing the
path might lead to blocking it.] In titanium, omega phase is brittle. This transition needs to
be inhibited. Current success is again thru experimentally combinatorial methods. Anything
that could shorten the process is a step forward.
3. To simulate large system -- necessary for reality -- models are necessary. We are
exploiting quantum Monte Carlo methods (that, in principle can be exact) to benchmark
these models. Viewgraph at http://www.physics.ohio-state.edu/~wilkins/junk/qmc.html
shows one example.
Summary:
Broad range of computational approaches model defect-induced properties aimed at predicting
and improving properties.
Benchmarking methods are essential to ensure model predictions are reliable.
This double focus needs a range of skills and interest from pure to applied.
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… and the others …
• Tin-Lun (Jason) Ho
Fundamental issues in dilute quantum gases: Scalar and Spinor Bose
condensates, Fermi gases with large spin, mixtures of quantum gases
in optical lattice and rapidly rotating potential, Boson mesoscopics,
processing quantum information with spinor Bose condensates;
Quantum Hall effects with internal degrees of freedom; Strongly
correlated electron systems; Quantum fluids
• C. Jayaprakash
Nonequilibrium phenomena; Fully developed turbulence; Strongly
interacting fermion systems
• Bruce R. Patton
Structure and properties of electroceramics; Grain growth in
anisotropic systems; Pattern recognition and optimization
• William F. Saam
Phase transitions at interfaces: wetting and roughening transitions;
Step interactions on solid surfaces and consequent phase transitions
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http://physics.ohio-state.edu/~cmt/osucmt.html
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