Academic Calendar

semester, 2010

Friday, January 1st 2010

Wednesday, March 10th 2010
5:00 pm:
Van Vleck Lecture in 150 Physics
Speaker: Anton Zeilinger, Institute for Quantum Optics and Quantum Information, University of Vienna
Subject: Quantum physics

Thursday, April 1st 2010
3:00 pm:
Refreshments will be served

Tuesday, April 6th 2010
4:40 pm:
Thesis Defense in 143 Physics
Speaker: Mitchell Ahrens, University of Minnesota
Subject: Neutrinos and Plastic Bottles: A Measurement of the Rate of Water Vapor Diffusion Through HDPE and Buna-N
This is the public portion of Mr. Ahrens' Thesis Defense

Monday, April 19th 2010
4:40 pm:
Speaker: Tanner Prestegard, University of Minnesota
Subject: Effect of Hadron Calorimeter Segmentation on Electron Identification in the Compact Muon Solenoid.
This is the public portion of Mr. Prestegard’s Senior Honors Thesis Defense

Tuesday, April 20th 2010
4:40 pm:
Speaker: Brian Moth, University of Minnesota
Subject: Simulation of a newly discovered liquid crystal phase

Monday, April 26th 2010
4:40 pm:
Speaker: Tyler Hennen, University of Minnesota
Subject: Magnetic Force Macroscopy
This is the public portion of Mr. Hennen’s Senior Honors Thesis Defense

Wednesday, April 28th 2010
4:40 pm:
Speaker: David Stark, University of Minnesota
Subject: The Recovery of Massive Stars from Giant Eruptions
This is the public portion of Mr. Stark’s Senior Honors Thesis Defense

Thursday, April 29th 2010
4:40 pm:
Speaker: Adam Peterson, University of Minnesota
Subject: Muon Calorimetry in the CLEO-c Experiment
This is the public portion of Mr. Peterson’s Senior Honors Thesis Defense

Friday, April 30th 2010
10:00 am:
Speaker: Grant Remmen, University of Minnesota
Subject: Distortion of Black Holes caused by motion relative to the Cosmic Microwave Background
This is the public portion of Mr. Remmen’s Senior Honors Thesis Defense

Monday, May 3rd 2010
4:40 pm:
Speaker: Niclole LaHaye, University of Minnesota
Subject: Observation of the Moses Effect in Pure and Salt Water Solutions
Students are welcome to read the paper and come discuss! (Professors are less welcome.)

Thursday, May 6th 2010
4:40 pm:
Speaker: Nathan Mirman, University of Minnesota
Subject: Study of Bin Migration in Z Boson Rapidity Measurement at CMS

Monday, May 10th 2010

Tuesday, May 11th 2010
1:00 pm:
Thesis Defense in 236 Physics
Speaker: Edwin Scott Bowman, University of Minnesota
Subject: Linear Sigma Model at Finite Temperatures and Chemical Potentials
This is the public portion of Mr. Bowman’s Thesis Defense

Saturday, May 15th 2010

Monday, May 24th 2010

Monday, May 31st 2010

Monday, June 7th 2010

Wednesday, June 9th 2010

Thursday, June 10th 2010
1:30 pm:
Ph. D. Thesis Defense in Physics 157
Speaker: Shun Wang, University of Minnesota
Subject: Investigating the orientational order in liquid crystals
This is the public portion of Shun Wang’s Thesis Defense

My thesis is composed of two projects. The first one is the investigation of a reversed phase sequence, which subsequently leads to the discovery of a novel Smectic-C liquid crystal phase. The 10OHFBBB1M7 (10OHF) compound, shows a reversed phase sequence with SmC_d4 phase at a higher temperature than the SmC phase. This phase sequence is stabilized by moderate doping of 9OTBBB1M7 (C9) or 11OTBBB1M7 (C11). To further study this unique phase sequence, the mixtures of 10OHFBBB1M7 and its homologous have been characterized by optical techniques. In order to perform the resonant X-ray diffraction experiment, we have added C9 and C11 compounds to the binary mixtures and pure 10OHF. In two of the studied mixtures, a new smectic-C liquid crystal phase with six-layer periodicity has been discovered. Upon cooling, the new phase appears between the SmC_alpha phase having a helical structure and the SmC_d4 phase with four-layer periodicity. The SmC_d6 phase shows a distorted clock structure. Three theoretical models have predicted the existence of a six-layer phase. However,our experimental findings are not consistent with the theories.

The second project involves the mixtures of liquid crystals with different shapes. The role of different interactions in stabilizing the antiferroelectric smectic liquid crystal phases have been a long standing questions in the community. By mixing the antiferroelectric smectic liquid crystal with achiral liquid crystal molecules with rod and hockey-stick shapes, we see distinct different behaviors. In the case of the mixtures of chiral smectic liquid crystals with rod-like molecues, all the Smectic-C* variant phases vanish with small amount of doping. However, the hockey-stick molecule is much less destructive compared to the rod-like molecule. This suggest that the antiferroelectric smectic liquid crystal molecules may have a shape closer to a hockey-stick other than a rod.

Friday, June 11th 2010
3:00 pm:

Monday, June 14th 2010

Monday, June 21st 2010
1:30 pm:
Ph. D. Thesis Defense in 435 Physics
Speaker: Eric Garlid, University of Minnesota
Subject: Electrical Detection of the Spin Hall Effect in Ferromagnet-Semiconductor Heterostructures

My thesis investigates the effects of spin-orbit coupling on spin
transport in Ferromagnet/Semiconductor heterostructures. Spin-orbit coupling is a relativistic phenomenon that couples the spin of an electron to its momentum by means of a momentum-dependent effective magnetic field. The effects of spin-orbit coupling in bulk InGaAs are observed by measuring the direct spin Hall effect, where an applied charge current induces a perpendicular spin current. The spins are oriented perpendicular to the flow directions of both the charge current and the spin current.
This spin current leads to an out-of-plane spin accumulation that is
opposite in sign at opposite edges of the channel. The spin accumulation
is identified through the observation of a Hanle effect in the Hall
voltage measured by pairs of ferromagnetic contacts. The data are fit
using a model which includes spin diffusion, precession, and relaxation.
We use the parameters determined from the fit to calculate the spin Hall
conductivity. We find that the magnitude of the spin Hall conductivity is
in agreement with models of the extrinsic SHE due to ionized impurity
scattering. By analyzing the dependence of the spin Hall signal on channel
conductivity we determine the contributions of both skew and side jump
scattering to the total spin Hall conductivity. We calculate that the
spin-orbit coupling parameter is larger than predicted by standard k•p
perturbation theory.

Monday, July 5th 2010

Friday, July 9th 2010
1:30 pm:
Thesis Defense in 402 Walter Library 
Speaker: Dan Weisz, University of Minnesota
Subject: The History of Star Formation in Nearby Dwarf Galaxies
This is the public portion of Mr. Weisz's Ph.D. final oral exam.

Tuesday, July 13th 2010
10:30 am:
Speaker: Ruihua He, Stanford University
Subject: Experimental Studies of High-Tc Cuprate Superconductors with Density Wave Correlations

High-Tc cuprate superconductors remain the source of central intellectual challenges for condensed matter physicists two decades after their discovery. Accumulating evidence suggests possible ubiquity of coexisting superconducting and density wave correlations in the ground state of these materials. As both correlations in their spatially incoherent forms can in principle produce a pseudogap in the excitation spectrum, the nature of the pseudogap widely seen in cuprates above Tc comes to forefront of debate. I have been trying to address the relationship triangle between the pseudogap, superconductivity and density waves, by mainly using angle-resolved photoemission spectroscopy (ARPES) to study the momentum spaces of single-layer La-based (La214) and Bi-based (Bi2201) cuprates.

In this talk, I will first briefly mention our ARPES-neutron scattering joint effort (in collaboration with Tohoku University) in the stripe-ordered state of La214. We found around the 1/8 doping level a dual nature of the pseudogap (in LBCO) and a doping-dependent crossover between localized- and
itinerant-spin ground-state physics (in 1% Fe-doped LSCO). I will then focus on our ARPES findings in both the pseudogap and superconducting states of nearly optimally-doped Pb-Bi2201 obtained over unprecedented momentum, energy and temperature ranges. They suggest that the pseudogap is a broken-symmetry state that is density-wave like and distinct from homogeneous superconductivity; it explicitly coexists with coherent superconductivity below Tc, causing a striking, momentum-dependent distortion of the high-Tc ground state.

Tuesday, August 10th 2010
12:00 pm:
Special Lecture in Physics 210
Speaker: Hans Courant, University of Minnesota
Subject: First-hand account of the Manhattan Project
Note change of venue, again!

Wednesday, August 11th 2010
1:30 pm:
Speaker: Brian Andersson, University of Minnesota
Subject: Lecture demonstration apparatus demonstrated

We will perform some of the more popular (and noisy) lecture demonstrations.

Monday, August 23rd 2010

Thursday, August 26th 2010
08:00 am:
Physics Force Public Show in Carousel Park Stage, Minnesota State Fair

Friday, September 3rd 2010

Monday, September 6th 2010

Tuesday, September 7th 2010

Friday, September 24th 2010
12:00 pm:
Physics Force Public Show in Coffman Union
Public shows are free and open to the public. No tickets or reservations required.

Friday, October 15th 2010
2:30 pm:
Thesis Defense in Physics 157
Speaker: Steven Gardeen, University of Minnesota
Subject: Human Auditory Source Discrimination.

Saturday, October 16th 2010
08:00 am:
Gravitational Waves 2010 Workshop in Mayo Memorial Auditorium
Please contact gw2010 (@) for more information about the event.

Thursday, November 4th 2010
10:00 am:
Thesis Defense in 150 Physics
Speaker: Jesse Woodroffe, University of Minnesota
Subject: Ultra Low Frequency Waves, Magnetic Pulsations, and the Ionospheric Alfven Resonator
This is the public portion of Jesse Woodroffe's thesis defense.

Thursday, November 11th 2010
11:30 am:
Come find out about careers in physics, take a lab tour and enjoy free pizza.
6:30 pm:
See a Physics Force Show, take a lab tour and win a copy of the Physics of Super Heroes!

Saturday, November 13th 2010
10:30 am:
Physics Force Public Show in Coffman Union
Public shows are free and open to the public. No tickets or reservations required.
12:00 pm:
Physics Force Public Show in Coffman Union
Public shows are free and open to the public. No tickets or reservations required.

Friday, December 10th 2010
2:30 pm:
Probability Seminar in Vincent Hall 207
Speaker: Jun Yin, Harvard University
Subject: Random Matrix Theory: A short survey and recent results on universality

Random matrix theories have fascinated both mathematicians and physicists since they were first introduced by Wishart and Wigner. Today we can find numerous applications and connections of random matrix theory to the following fields: probability theory, financial math, number theory, quantum chaotic system, biology, even wireless communication. In this talk, we give a short review of the main historical developments of random matrix
theory. We emphasize both the theoretical aspects, and the application of the theory, including the recent works on the universalities of random matrices.

Monday, December 27th 2010

Tuesday, December 28th 2010

Wednesday, December 29th 2010

Thursday, December 30th 2010

Friday, December 31st 2010

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