Steve Sharpe
Professor of Physics
Department of Physics, University of Washington
I joined the
particle theory group in the
Physics Department at the University of Washington in 1988.
My current research interests focus on
lattice gauge theory, in particular the calculation of weak matrix
elements which are needed to constrain the Standard Model
of particle physics, as well as the idea of "large-N reduction",
whereby in the limit of the large number of
colors one can reduce the volume of the theory to
a single point. I am involved in the US national lattice QCD collaboration,
"USQCD", as a member of the Executive Committee (see links below).
My present graduate student is Max Hansen; I am also working closely
with a visiting student from Krakow, Mateusz Koren.
My previous graduate students
are Keith Clay (joint with Steve Ellis, presently on faculty
at Green River Community College), Yan Zhang (was postdoc at Beijing U.,
present whereabouts unknown),
Noam Shoresh (joint with David B. Kaplan, first postdoc at Boston U,
now on the research staff at the Broad Institute, Cambridge, MA)
Ruth Van de Water (first postdoc at Fermilab, now a Goldhaber fellow
at Brookhaven National Lab)
and Jackson Wu (first postdoc at Triumf, Vancouver, now a postdoc
at the University of Bern, Switzerland),
and Andrew Lytle (postdoc at Univ. Southampton, England).
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Publications.
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Lecture notes, and some recent talks:
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Talk
at workshop on new fermion discretizations,
Feb, 2012, Yukawa Institute, Kyoto, 2012.
This talk has 2 parts. The first is
an investigation of whether one can use one staggered
fermion to study the lightest four physical flavors (u,d,s,c). My conclusion
is that it is impractical.
The second part is an analysis of the symmetries, vacuum and pion spectrum
of two types of "staggered-Wilson fermions": that proposed by Adams having
2 light fermions, and that proposed by Hoelbling (and its variants)
having either 1 or 2 light fermions. I conclude that the former scheme has
a number of attractive properties, while the later suffers from rotation
breakdown in the continuum limit, unless one adds counterterms and fine tunes.
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Colloquium
("Lattice QCD: successes, challenges and future outlook")
at Seoul National University, Korea, November 16, 2011.
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Talk
at ECT* workshop on "Chiral Dynamics with Wilson fermions",
Oct. 24-28th, 2011, Trento, Italy.
This gives an introduction to Wilson Chiral Perturbation Theory
and the predictions for the phase structure at non-zero lattice
spacing, and presents some new work with student Max Hansen.
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Talk
at USQCD "All Hands Meeting",
Jefferson Lab, May 7th 2011. This covers both
the projects supported by USQCD allocations noted above.
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Seminar,
"Large-N QCD from simulations on a single site?"
,
at Brookhaven Nat. Lab, March 23rd, 2011.
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Talk
at DOE site visit, December 2010, summarizing recent research.
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Review talk
"Kaon Physics from the Lattice" ,
presented at
"Lattice QCD Meets Experiment Workshop 2010" ,
Fermilab, April 26-27, 2010.
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"Subatomic physics and lattice calculations", GDR meeting,
CNRS, Marseille, June 25-27, 2008.
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Updated lectures on
"Applications of chiral perturbation theory to lattice QCD"
.
These lectures
describe the use of effective field theories to extrapolate results
from the parameter region where numerical simulations of lattice QCD
are possible to the physical parameters (physical quark masses,
infinite volume, vanishing lattice spacing, etc.). After a brief
introduction and overview, I discuss three topics:
-
(1)
Chiral
perturbation theory in the continuum, and lessons for lattice
calculations;
-
(2)
The inclusion of
discretization effects into chiral perturbation theory, focusing on
the application to Wilson and twisted-mass lattice fermions;
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(3)
Extending chiral perturbation theory to describe partially quenched
QCD, and (this is new) a discussion of the relationship of the possible
ambiguity in the definition of $m_u=0$ and the existence of continuum
PQ theories.
-
I organized a summer school at the INT in 2007 on
``Lattice QCD and its applications''.
-
I am a member of the executive committee of the
USQCD
collaboration, which has obtained support from DOE
for computational resources and support.
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I am a co-PI on a
SciDAC2
(Scientific Discovery through Advanced computing---round 2) proposal
aimed at creating a national infrastructure for lattice gauge computing.
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With collaborators Weonjong Lee and Chulwoo Jung,
I am calculating the kaon B-parameter and other matrix elements using
improved staggered fermions, using USQCD resources.
The project web page is here .
-
Ex-UW graduate student Andrew Lytle and
I are calculating matching factors using
non-perturbative renormalization for improved
staggered fermions.
The project web page is here .
Teaching (recent plus some old classes)
- SPRING 2011:
Physics 519:
Graduate QM (third quarter).
- WINTER 2011:
Physics 518:
Graduate QM (second quarter).
- AUTUMN 2010:
Physics 517:
Graduate QM (first quarter).
- SPRING 2009:
Physics 507:
Physical Applications of Group Theory.
- WINTER 2009:
Physics 486 and 495:
Seminar on Current Problems in Physics and Senior Honors Seminar.
- AUTUMN 2008:
Physics 505:
Graduate Mechanics (and an introduction to chaos).
US mail: Stephen R. Sharpe
Department of Physics
University of Washington
Box 351560
Seattle, WA 98195-1560
Office: B406 Physics-Astronomy Building
Email: sharpe@phys.washington.edu
Phone: (206) 685-2395
FAX: (206) 543-5923 or 685-0635
Steve Sharpe
<
sharpe@phys.washington.edu>
Last modified: 12/2010