Transcript Theoretical Studies of Josephson Arrays, High Temperature

Theory of Superconducting and Electromagnetic
Properties of Some Nanostructured Materials
David Stroud, Ohio State University
NSF DMR04-13395
Above: series of Josephson junctions
(small superconducting elements
which behave like pendulums)
coupled to this nano-tuning fork
(indicated as piezoelectric crystal).
Below: black curve shows vibrating
``tuning fork” driven by junctions.
Amplitude
• Research Highlight:
Nanostructured
Superconductors
• A superconductor is a material
which conducts electricity with
no resistance. A nanoscale
superconductor has
dimensions on the scale of
1/1,000,000,000 meters.
• We have shown that such
small superconductors can be
coupled together by a
``nanomechanical oscillator’’
(basically a nanoscale tuning
fork).
• See B. R. Trees, S. Natu, and
D. Stroud, Phys. Rev. B72,
214524(2005)
TIME
Theory of Superconducting and Electromagnetic Properties of
Some Nanostructured Materials
David Stroud, Ohio State University
NSF DMR04-13395
Some potential applications:
1. When the Josephson
junctions couple together,
they can radiate energy.
Good source of microwaves
for signal processing.
2. If junctions are really small,
they can act like ``quantum
bits’’. A quantum bit is a
tiny element of a ``quantum
computer,’’ which may be
much faster than a
conventional computer.
The nano tuning-forks can
couple these quantum bits
together to produce a
system for carrying out very
fast computation.
Contributions to Education:
Six grad students (Daniel ValdezBalderas, Ivan Tornes, Kohjiro Kobayashi,
Kwangmoo Kim, Vishwesha Guttal), one
postdoc (Sung Yong Park), one
undergrad REU student (Bryan Chen),
another undergrad (Stefan Natu), and
sabbatical visitor Brad Trees have
contributed to this work. Ivan Tornes is
now a staff scientist at Battelle; Park has a
postdoc at Northwestern.
New course developed: “Introduction to
Quantum Computing” based partly on
research findings from this work. Notes
are available on my web site