Title: About C, P and T
Abstract:
We introduce the concepts of charge conjugation (C),
parity (P) and time-reversal (T) and explain how it is that
measurment of the violation of CP is a hot topic in fundamental
experimental physics these days.
Title: Monte Carlo Simulations of Spin Systems
Title: Quanutum gravity and physics: how the former may become the latter
Abstract:
Quantum gravity is purported to be the theory which underlies both
quantum theory and general relativity. I will introduce the subject,
emphasizing recent results which suggest that space is discrete.
Discrete geometry may have an observational signature and I will
describe limits on such weird geometry by astrophysical observations.
I will also argue that, in the not too distant future, quantum gravity
may become physics and enjoy contact with observation and, perhaps, experiment.
Title: Photon-induced magnetization reversal in single-molecule magnets
Abstract:
Single-molecule magnets (SMM) have been subject to intensive research for
more than a decade now because of their unique properties such as macroscopic
quantum tunneling. Recent work in this area is focused on whether SMM are
suitable candidates to realize quantum computation, as proposed theoretically.
We use millimeer wave radiation to manipulate the populations of the energy
levels of a single crystal molecular magnet Fe8. When a continuous wave
radiation is in resonance with the magnetic dipole transitions (ms=1)
between the energy levels, the equilibrium magnetization exhibits a dip. The
position of this dip varies linearly with the radiation frequency. We will
describe our experimental results, which provide a lower bound of 0.17 ns for \the relaxation time.
Title: Interference, Complementarity, Entanglement and all that Jazz
Abstract:
Technology has advanced to the point where it is possible for
undergraduates to perform experiments exploring fundamental aspects of
quantum mechanics, such as wave-particle duality, entanglement,
and tests of Bell inequalities. At Whitman College we are
developing a series of undergraduate laboratories and I will
describe some of these. In one we perform an
interference experiment with single photons where we clearly
show that the individual photons behave both as waves and particles.
This experiment is consistent with Bohr's principle of
complementarity, but challenges some oft-held beliefs surrounding it.
In another experiment, involving entangled photon pairs, we can
demonstrate the operation of a "quantum eraser". We show that
measurements performed on one beam can change the visibility of
a fringe pattern in another, spatially separated beam.
Title: B-factories: powerful tools to probe the matter-antimatter asymmetry of the universe
Title: Atmospheric Physics in the Kitchen
Abstract:
In this talk, I will use examples drawn from everyday experience in the
kitchen, along with basic dynamics and thermodynamics, to illustrate
processes of fundamental importance to the structure and variability of
the atmosphere. Three topics will be addressed: (1) how can you build
an altimeter from a gas stove and a thermometer? (2) why do boiling kettles
steam? and (3) why do leaves in a stirred cup of tea pile up in the
centre of the cup, and what does this have to do with wintertime storms?
Title: Einstein's Miraculous Year
Abstract:
Einstein's miraculous year was the culmination of his earlier efforts
to master classical physics and criticize and supercede certain
of its features. After a brief review of classical mechanics and 19th
century optics and electrodynamics of moving bodies, Einstein's work in
About the speaker:
John Stachel is Professor Emeritus of Physics and Director of the
Center for Einstein Studies at Boston University. He was the founding editor
of The Collected Papers of Albert Einstein, editor of
"Einstein's Miraculous Year" (Princeton University Press), author of
"Einstein from 'B' to 'Z' " (Birkauser Boston) and of the forhtcoming
two-volume collection of his papers NOT about Einstein:
"Going Critical" (Kluwer).
Title: Magnetic Quantum Tunneling in Single Molecule Magnets
Abstract:
Single molecule magnets (SMMs) are magnetic nanostructures
that consist of a core of strongly exchange-coupled transition metal
ions with a large collective magnetic moment per molecule, thus far up
to 51 Bohr magnetons, and a predominantly uniaxial magnetic anisotropy.
Their molecular nature enables experimental studies of nearly
monodisperse ensembles of nanomagnets with well-defined size, shape,
chemical composition, and magnetic anisotropy. This talk will present
experiments that address the origin of magnetic quantum tunneling (MQT)
in the prototype SMM Mn12-acetate and, in particular, the nature of the
transverse interactions that produce quantum tunneling. Recent
experiments that employ microwave fields to modulate MQT and
characterize quantum superpositions states of "up" and "down"
spin-projections will also be described.
Abstract:
Neutrinos are the smallest particles in the Standard Model, with
a mass expected to be zero. However, many experiments have observed
neutrino oscillation, which depends on a non zero neutrino mass.
I will discuss neutrinos, neutrino oscillation, the past and future
levels of students. In the second half of my talk, I will go over
general tips about graduate school, how to get in, and what to do
when you get there.
Meltem Duran
Tarun Menon
Nathaniel Reden
Title: The Role of Buried Charged Groups in Proteins
Abstract:
Proteins contain acidic and basic residues which would be ionized in aqueous solution. The Born solvation energy stabilizes charges in water. By having charged groups on their surface helps proteins remain soluable. A small, but significant number of ionizable residues are buried in the protein. I will describe how electrostatic analysis can be used to calculate the equilibrium ionization state of these residues by computing the interactions amongst charges and dipoles in the protein. In addition, I will describe how these buried acidic and basic groups function in pumping protons (H+) across cell membranes in proteins such as bacteriorhodopsin.
Title: How neurons do integrals
Abstract:
Neurons that command the eyes to move generate action potentials, or "fire," at a rate that is proportional to eye velocity. To maintain the eyes at a fixed position, motor neurons that control the muscles of the eye fire at a rate that is proportional to eye position; in the absence of their firing, spring-like forces return the eyes to the center of the head. The transformation of velocity-coded eye movement commands to position-coded firing of motor neurons is accomplished by an area of the brain known as the oculomotor neural integrator. In this talk, I will describe the experimental characterization of the goldfish neural integrator, mathematical models of the neuronal mechanisms that enable the velocity-to-position integration to be performed, and connections between neural integration and the storage of short-term memories.
Title: Gamma ray astrophysics
Abstract:
Very high energy gamma ray science has progressed dramatically in the last 15 years. Several new telescope arrays currently being commissioned will push this field much farther in the next decade, combining many of the scientific interests of astrophysics and particle physics. On the astrophysics side, gamma ray studies drive the effort to understand some of the most powerful accelerators in the universe. On the particle physics side, very high energy gamma rays can be used to probe fundamental questions in physics. I will discuss two topics in the latter category, Lorentz breaking and dark matter, that have especialy captured the interest of the scientific community and that are currently being pursued in gamma ray experiments.
Title: Parity Nonconservation in Atoms: The Evolving Story
Abstract:
Study of parity nonconservation (PNC) in heavy atoms provides atomic-physics test of the electroweak Standard Model and led to a first measurement of the nuclear anapole moment. The PNC interaction leads to a non-zero amplitude for transitions otherwize forbidden by the parity selection rule, such as the 6s-7s transition in cesium. Combining experimental measurements and theoretical calculations of the PNC amplitude permits one to infer the value of the weak charge and compare it with the value predicted by the Standard Model. In this talk, I will give an overview of the status of the parity nonconservation studies in heavy atoms. I will specifically focus on the calculation of the Cs PNC amplitude and the resulting analysis which yielded the value of the weak charge. The PNC experiment in Cs, combined with the calculation of the spin-depended PNC amplitude, also yielded the value of the nuclear anapole moment and allowed us to place constraints on PNC meson coupling constants which were found to be in disagreement with those obtained from other nuclear parity violating experiments. I will present preliminary results of the new calculation of spin-dependent amplitude in Cs conducted using a relativistic all-order method and discuss the issue of the accuracy of the atomic calculations needed to derive the value of the anapole moment.
Title: High-Speed Schlieren Photography of Ice Cubes, Soap Bubbles, Candle Flames and Shock Waves
Abstract:
In conjunction with the Mead Art Museum exhibit Quicker Than A Wink: Photographs By Harold Edgerton J. Kim Vandiver will deliver a lecture "High-sped schlieren photography of ice cubes, soap bubbles, candle flames and shock waves." The lecture is sponsored by the Departments of Astronomy and Physics.
About the speaker:
Vandiver, Dean for Undergraduate Research and Director of the Edgerton Center at MIT, was a colleague of Edgerton's and has continued his pioneering work on ultra-high speed photography. He will show his beautiful and spectuacular images of everyday events, revealing hitherto-unseen phenomena, as well as explaining techniques for making such photographs. The lecture will be at a non-technical level and the public is invited to attend.
Abstract:
TBA
Abstract:
Her research group does interdisciplinary science, and this seminar should
be accessible to physicists, chemists, and biologists alike.
Mammalian cells are surrounded by an outer wall or "plasma membrane"
of proteins and lipids arranged in opposing leaflets of a bilayer.
There is growing evidence that this membrane is not uniform, but
instead laterally phase separates into "raft" domains rich in
particular lipids and proteins. We study a simpler physical model of
cell membranes, giant unilamellar vesicles (GUVs). Liquid domains in
vesicles exhibit interesting behavior: they collide and coalesce, can
finger into stripes, and can bulge out of the vesicle. We use
fluorescence microscopy to directly observe liquid domains in the
vesicles. We cross miscibility phase transitions by changing
temperature. Using results from both fluorescence microscopy and NMR
studies, we quantitatively construct tie-lines on phase diagrams.
These tie-lines allow us to estimate free energies to transfer lipids
between phases. We also find that it is possible to capture domains
in lipid layers on glass substrates.
About the speaker:
Dr. Sarah L. Keller is an assistant professor in the
Department of Chemistry at the University of Washington in Seattle.
Her research group includes an interdisciplinary team of postdocs,
graduate students, and undergraduates.
Dr. Keller's group studies liquid domains in lipid bilayers and monolayers. In recent work, her group has advanced our knowledge of the miscibility phase behavior of model mixtures of phospholipids and cholesterol, and established tie-lines.
Abstract:
TBA
Title: TBA
Abstract:
TBA
Meltem Duran
Tarun Menon
Nathaniel Reden
Rishi Chaudhuri
Ben Heidenreich