This Week at Physics

<< Fall 2013 Spring 2014 Fall 2014 >>

Events During the Week of February 9th through February 16th, 2014

Sunday, February 9th, 2014

Wonders of Physics
Physics of Dimensions
Time: 1:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Wonders of Physics
Physics of Dimensions
Time: 4:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Monday, February 10th, 2014

Cosmology Journal Club
An Informal discussion about a broad variety of arXiv papers related to Cosmology
Time: 12:15 pm
Place: 5242 Chamberlin Hall
Abstract: Please visit the following link for more details:
    http://cmb.physics.wisc.edu/journal/index.html
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (lzhang263@wisc.edu)
Host: Peter Timbie
Add this event to your calendar

Faculty Candidate Seminar
Notes from Underground: Direct Dark Matter Searches and Single Phase Liquid Argon Detectors
Time: 4:00 pm
Place: 4274 Chamberlin Hall
Speaker: Kim Palladino, MIT
Abstract: Evidence for the existence of Dark Matter from astronomical observations abounds, while experimentalists are still in pursuit of a confirmed laboratory 'direct' detection. Currently in the dark matter field, contradictory experimental results of allowed signal regions and excluding upper limits exist and new experiments will be coming online in the near future to shed light on the matter. MiniCLEAN and DEAP-3600 are liquid argon experiments for the direct detection of dark matter under construction at SNOLAB, located 6800 feet underground in an active nickel mine in Sudbury, Ontario. The implications of their unique design will be discussed in the context of the wider search for dark matter.
Host: Sridhara Dasu/Lisa Everett
Add this event to your calendar

Tuesday, February 11th, 2014

Chaos & Complex Systems Seminar
How does dark matter interact with us?
Time: 12:05 pm
Place: 4274 Chamberlin
Speaker: Yang Bai, UW Department of Physics
Abstract: Dark Matter occupies about one quarter of the total energy of our Universe. Additional interactions between dark matter and ordinary matter beyond the gravitational one may exist. In this talk, I will discuss how much we have learned about all dark matter interactions with us.
Host: Clint Sprott
Add this event to your calendar

"Physics Today" Undergrad Colloquium (Physics 301)
Counting Microwave Photons
Time: 1:20 pm
Place: 2223 Chamberlin
Speaker: Maxim Vavilov, UW Madison Department of Physics
Add this event to your calendar

Wednesday, February 12th, 2014

Department Meeting
Time: 12:15 pm
Place: 5310 Chamberlin Hall
Add this event to your calendar

Faculty Candidate Seminar
Exploring Fundamental Physics through Measurements of the Cosmic Microwave Background
Time: 4:00 pm
Place: 4274 Chamberlin Hall
Speaker: Bradford Benson, University of Chicago
Abstract: The cosmic microwave background (CMB) provides a unique window into the early universe and cosmology. The CMB is generated by well-understood dynamics, only ~400,000 years after the Big Bang, that enables precise calculation of its observable features and which directly connects new measurements to fundamental physics. I will discuss the latest measurements of the CMB by the South Pole Telescope (SPT), including the first detection of a curl-only component (B-modes) in the polarization of the CMB by SPTpol. I will describe the instrumentation and detector technology in development for next-generation experiments, including SPT's next camera, SPT-3G, and a future ground-based CMB experiment, CMB-S4. The science goals of these experiments aim to answer some of the most exciting questions in cosmology: to differentiate between dark energy and modified gravity to explain the origin of cosmic acceleration, to test and constrain physics at grand-unified theory energy scales (~1e16 GeV), to measure the sum of the neutrino masses at a sensitivity below the minimum mass expected from neutrino oscillations (<0.06 eV), and to precisely constrain the relativistic energy density of the universe and any "dark radiation" component.
Host: Albrecht Karle/Peter Timbie
Add this event to your calendar

Thursday, February 13th, 2014

NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Hadronic Interaction Models and the Interpretation of Astroparticle Data
Time: 2:30 pm
Place: 4274 Chamberlin Hall
Speaker: Dimitra Atri, Blue Marble Space Institute of Science
Abstract: The interpretation of astroparticle data from both ground and space-based instruments depends strongly on the hadronic interaction models underpinning the emission mechanism. I will demonstrate the model dependence using recent observations from the Ooty air shower array and Fermi LAT. I will also discuss how the choice of hadronic interaction models could affect the interpretation of neutrino and gamma ray measurements with IceCube and CTA.
Host: Justin Vandenbroucke
Add this event to your calendar

Astronomy Colloquium
Asymmetries in Protoplanetary Transition Disks
Time: 3:30 pm
Place: 4421 Sterling Hall
Speaker: Hui Li, Los Alamos National Laboratory
Abstract: Particle energization in astrophysical systems is a challenging yet fascinating subject. Observations from radio to gamma-rays of AGN jets, supernova remnants, pulsars, gamma-ray bursts, etc., have provided important clues. In this talk, we explore the energy conversion processes in a parameter regime when the magnetic energy density overwhelms the particle energy density (including its rest mass energy density). Such a condition has been discussed in the context of AGN jets and pulsars. We present two-dimensional and three-dimensional relativistic, full kinetic simulations that show fast magnetic reconnection can occur in highly magnetized plasmas, with the magnetization parameter ranging from unity to 1600. The fast magnetic dissipation leads to a fast, nonthermal particle acceleration, yielding a power law distribution with a hard spectrum. Detailed analyses show that the acceleration in the power-law range is mainly by a Fermi-like mechanism in the relativistic flows generated by reconnection. Implications for observations will be discussed.
Host: Professor and Dept Chair Ellen Zweibel
Add this event to your calendar

Faculty Candidate Seminar
Engineering New Electronic States in Graphene Heterostructures: Massive Dirac Fermions, Hofstadter’s Butterfly and the Quantum Spin Hall Effect
Time: 4:00 pm
Place: 4274 Chamberlin Hall
Speaker: Benjamin Hunt, MIT
Abstract: Van der Waals heterostructures represent a new and surprising direction in nanoscale device engineering: we stack isolated two-dimensional crystals to create layered structures with atomic precision. The layer-by-layer assembly allows us to introduce a new design parameter - the interlayer twist angle - which can have profound consequences for the engineering of electronic states based on tunable interactions between adjacent layers. In this talk, I will discuss recent experiments at MIT in which we have used a hexagonal boron nitride (hBN) layer to modify the electronic bands of monolayer graphene in a van der Waals heterostructure, inducing a sizable bandgap at the charge neutrality point and imparting a mass to the normally massless Dirac charge carriers. The bandgap occurs only in samples in which the twist angle between the graphene and hBN crystals is small, resulting in a long-wavelength moirA(c) that acts as a superlattice potential; by adjusting the twist angle the bandgap can be tuned. The moirA(c) superlattice potential also allows us to study the problem of a charged particle in a periodic potential and magnetic field aEuro" the so-called Hofstadter problem aEuro" whose theoretical solution exhibits a rare instance of fractal behavior in a quantum-mechanical energy spectrum.

I will also discuss our recent studies of weakly-coupled graphene-hBN heterostructures in which massless Dirac fermions in graphene exhibit a quantum spin Hall effect, a fascinating example of a aEurooesymmetry-protected topological phaseaEuro of which the more familiar contemporary examples are the edge and surface states of the topological insulators.
Host: Mark Eriksson/Sridhara Dasu
Add this event to your calendar

Friday, February 14th, 2014

Theory Seminar (High Energy/Cosmology)
Title to be announced
Time: 2:15 pm
Place: 5280 Chamberlin Hall
Host: Jordi Savado
Add this event to your calendar

Physics Department Colloquium
First Evidence for Energetic Cosmic Neutrinos with IceCube
Time: 3:30 pm
Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
Speaker: Albrecht Karle, University of Wisconsin Department of Physics
Abstract: Neutrino astronomy was proposed in the early 1960s as way to explore high energy phenomena in Universe. After 20 years of experimental efforts towards a large neutrino telescope at the South Pole, IceCube has come in full operation since May 2011. One of the primary goals of IceCube is the search for an energetic astrophysical neutrinos flux. I will discuss searches for high-energy neutrinos (energies > 100 TeV) with IceCube, which have recently produced the first evidence for a flux of neutrinos beyond expectations from neutrinos generated in the EarthaEuroTMs atmosphere. This includes the detection of events with energies above 1000 TeVaEuro"the highest energy neutrinos ever observed. I will discuss our recent findings as well as strategies underway that may help to shed more light on the origin of highest energy particles in the Universe.
Poster: http://www.physics.wisc.edu/twap/posters/2014/3174.pdf
Video: http://www.physics.wisc.edu/vod/2014/02/14.html
Add this event to your calendar

Saturday, February 15th, 2014

Physics Fair
7th Annual Physics Fair
Time: 11:00 am
Place: Chamberlin Hall
Abstract: UW-Madison Physics Department Open House

Fun for the whole family! No tickets required!

Hands-on demos, research laboratory tours.
Explore the Ingersoll Physics Museum.
Host: UW-Madison Physics Department
Add this event to your calendar

Wonders of Physics
Physics of Dimensions
Time: 1:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Wonders of Physics
Physics of Dimensions
Time: 4:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Wonders of Physics
Physics of Dimensions
Time: 7:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Sunday, February 16th, 2014

Wonders of Physics
Physics of Dimensions
Time: 1:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

Wonders of Physics
Physics of Dimensions
Time: 4:00 pm
Place: 2103 Chamberlin
Speaker: Clint Sprott and colleagues, UW Department of Physics
Abstract: The 31st annual presentation of the popular outreach program for the public. Advanced free tickets are recommended.
Host: Clint Sprott
Add this event to your calendar

"This Week at Physics" poster: http://www.physics.wisc.edu/twap/posters/2014/2014-02-10.pdf

©2013 Board of Regents of the University of Wisconsin System