[Theory-seminars] Fwd: Please Save the Date: Final Oral Examination for the Ph.D. Degree- Hao Shi - Monday, March 27 at 1:30 PM

[Mary Fox]

-------- Forwarded Message --------
Subject: 	Please Save the Date: Final Oral Examination for the Ph.D. 
Degree- Hao Shi - Monday, March 27 at 1:30 PM
Date: 	Thu, 9 Mar 2017 16:48:06 +0000
From: 	Wilkinson, Eleonor V <evwilk at wm.edu>
To: 	physics0607 at physics.wm.edu <physics0607 at physics.wm.edu>
CC: 	undergrads0607 at physics.wm.edu <undergrads0607 at physics.wm.edu>



*Physics Dissertation Defense***

*Hao Shi*

Monday, March 27, 2017

1:30 P.M.

Earl Gregg Swem Library, Ford Room

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*Title of Talk:**/Computational Studies of Strongly Correlated Quantum 
Matter/**//*

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*Abstract:*The study of strongly correlated quantum many-body systems is 
an outstanding challenge. Highly accurate results are needed for the 
understanding of practical and fundamental problems in condensed-matter 
physics, high energy physics, material science, quantum chemistry and so 
on. Our familiar mean-field or perturbative methods tend to be 
ineffective. Numerical simulations provide a promising approach for 
studying such systems. The fundamental difficulty of numerical 
simulation is that the dimension of the Hilbert space needed to describe 
interacting systems increases exponentially with the system size. 
Quantum Monte Carlo (QMC) methods are one of the best approaches to 
tackle the problem of enormous Hilbert space. They have been highly 
successful for boson systems and unfrustrated spin models. For systems 
with fermions, the exchange symmetry in general causes the infamous sign 
problem, making the statistical noise in the computed results grow 
exponentially with the system size. This hinders our understanding of 
interesting physics such as high-temperature superconductivity, 
metal-insulator phase transition. In this thesis, we present a variety 
of new developments in the auxiliary-field quantum Monte Carlo (AFQMC) 
methods, including the incorporation of symmetry in both the trial wave 
function and the projector, developing the constraint release method, 
using the force-bias to drastically improve the efficiency in Metropolis 
framework, identifying and solving the infinite  variance problem, and 
sampling Hartree-Fock-Bogoliubov wave function. With these developments, 
some of the most challenging many-electron problems are now under 
control. We obtain an exact numerical solution of two-dimensional 
strongly interacting Fermi atomic gas, determine the ground state 
properties of the 2D Fermi gas with Rashba spin-orbit coupling, provide 
benchmark results for the ground state of the two-dimensional Hubbard 
model, and establish that the Hubbard model has a stripe order in the 
underdoped region.

*Bio:*Hao Shi was born in Gugao, China, on July 13, 1986. He is 
fascinated with science and math since he was a kid. In 2008, he 
graduated with a Bachelor of Science degree in Physics from Nanjing 
University in Nanjing, China. In the same year, he joined Renming 
University in Beijing, China to study computational physics. He entered 
the College of William and Mary and joined Dr. Shiwei Zhang’s 
computational condensed matter physics group in Fall 2011. His research 
focuses on studying strongly correlated systems by Auxiliary Field 
Quantum Monte Carlo and other numerical methods. After graduation, he 
will work as a postdoctoral fellow at Center for Computational Quantum 
Physics in Flatiron Institute.

Open to the public.

******

*Eleonor V. Wilkinson*

Administrative Coordinator

The College of William & Mary-Physics
Small Hall, Room 123
300 Ukrop Way
Williamsburg, VA 23185

Telephone: 757-221-3503

Fax: 757-221-3540

find_us_on_facebook_badge 
<https://www.facebook.com/#%21/pages/William-Mary-Physics-Department/165186546866601?sk=wall>

Cheers,

Elle Wilkinson

The College of William & Mary

Physics Admin/REU Coordinator

evwilk at wm.edu <mailto:evwilk at wm.edu>

757-221-3503

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