Events - Weekly
April 2013 >>
|Sunday, April 14|
|Monday, April 15|
King-Wai Yau (Johns Hopkins) "Responses to Single Photons in Vision and to Single Odorant Molecules in Olfaction, and Their Implications"
Joseph Henry Room · 12:00 p.m.– 1:00 p.m.
Condensed Matter Seminar, Young S. Lee, MIT, Two faces of the kagomé lattice: quantum spin liquids and topological flat bands
I will describe experimental studies of new states of magnetism on the S=1/2 kagomé lattice. In particular, I will discuss results on two materials: one with antiferromagnetic exchange (herbertsmithite) and one with ferromagnetic exchange (Cu(1,3-bdc)).
Quantum spin liquids are new states of matter that are characterized by long-range entanglement and support exotic excitations. This year marks the 40th anniversary of the original proposal for such a state by Anderson; however, they have only recently been realized in experiments. Herbertsmithite is a leading candidate for having a quantum spin liquid (QSL) ground state. A recent breakthrough in crystal growth has allowed us to uncover a hallmark signature of the QSL state. Inelastic neutron scattering measurements reveal that the spin excitations are fractionalized, a remarkable first. Additional measurements, made possible by the crystals, further corroborate the identification of a QSL.
In contrast to the antiferromagnetic case, ferromagnetic moments on the kagomé lattice are not highly frustrated. Our neutron scattering measurements on Cu(1,3-bdc) confirm that the spins order at low temperatures. However, inelastic scattering reveals an interesting flat band in the magnon dispersion relations. Moreover, each band is separated by a gap from the other bands. I will discuss the role of the Dzyaloshinsky-Moriya interaction and the prospects of measuring new physics with topologically non-trivial magnon bands.
PCTS Seminar Room · 1:15 p.m.– 2:30 p.m.
|Tuesday, April 16|
Math Physics Seminar - Vieri Mastropietro, Univ of Milan, Italy, Universal finite size corrections and the central charge in non solvable Ising models
We investigate a non solvable two-dimensional ferromagnetic Ising model with nearest neighbor plus weak finite range interactions. We rigorously establish one of the predictions of Conformal Field Theory (CFT), namely the fact that at the critical temperature the finite size corrections to the free energy are universal. The corresponding central charge, defined in terms of the coefficient of the first subleading term to the free energy, is constant and equal to 1/2. Work in collaboration with A. Giuliani.
Jadwin A06 · 4:30 p.m.– 6:00 p.m.
Raymond & Beverly Sackler Lecture in Astrophysics, Bill Jones "The Universe in a New Light: The First Cosmological Results from the PLANCK Mission"
The precision and accuracy of the recently released Planck data are without precedent; the data from a single experiment provide all-sky images at wavelengths never before explored, covering more than three decades in angular scale with a signal dynamic range exceeding a factor of a million. These data open new avenues of research in fields ranging from Galactic astrophysics to cosmology. Our present Universe has shown herself to be both simple and elegant, and although her origins remain enshrouded in mystery, it appears that her past may have been more complex. While the Planck data have begun to inform us about the nature of cosmo-genesis, a new series of experiments are required to distinguish between competing theories of the origin of the Universe.
We will discuss the cosmological implications of the Planck data, and describe our current efforts to probe cosmic genesis with experiments like the Spider Antarctic long duration balloon experiment.
McDonnell A02 · 8:00 p.m.–10:30 p.m.
|Wednesday, April 17|
"Fundamental Physics and the LHC: A Progress Report"-Nima Arkani-Hamed- IAS
"Last July's discovery of the Higgs particle at the Large Hadron Collider was a triumph for both experiment and theory in fundamental physics. But the Higgs also introduces major conceptual paradoxes that strongly suggest we are missing essential new physical principles. Chief amongst these is the severe ``naturalness" or ``fine-tuning" problem, which arises in trying to answer a simple question: why is there a macroscopic universe? It has long been thought that this mystery would be solved by new symmetries or dynamics at the distance scales probed by the LHC. If so, what should we make of the absence of obvious signs of new physics at the LHC so far? Are entirely different kinds of explanations possible? And what should we be looking for from the LHC when it restarts in 2015? In this talk, I will summarize this excitingly confusing state of affairs, and discuss what we can hope to learn by 2020"
PPPL: Lyman Spitzer Building · 4:00 p.m.– 5:00 p.m.
|Thursday, April 18|
|Friday, April 19|
High Energy Theory Seminar - IAS - Jonathan Maltz, Stanford University - Light States in Chern-Simons Matter Theory Coupled to Fundamental Matter
Bloomberg Lecture Hall - Institute for Advanced Study · 1:30 p.m.– 2:30 p.m.
|Saturday, April 20|
25th Annual Physics Recital
Taplin Auditorium · 6:00 p.m.– 8:00 p.m.