Events at Physics |
Events During the Week of February 26th through March 4th, 2012
Monday, February 27th, 2012
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Neutrino Oscillation Physics at the South Pole
- Time: 11:00 am
- Place: 5280 Chamberlin Hall
- Speaker: David Jason Koskinen, Penn State
- Abstract: The discovery of neutrino oscillation, which leads to a non-zero neutrino mass, creates a host of interesting questions with relevance to particle physics, astrophysics, cosmology and beyond. After a brief review, I will cover some of the major oscillation topics and how the DeepCore sub-array, a low-energy extension of the IceCube neutrino observatory, offers new opportunities for neutrino oscillation physics in the tens of GeV energy region. Possible future extensions designed to drive the energy reach down to ~1 GeV in an initial stage (PINGU) and tens of MeV in a second stage (MICA) will conclude the talk.<br>
- Host: Halzen
Tuesday, February 28th, 2012
- Chaos & Complex Systems Seminar
- Dreaming and language evolution
- Time: 12:05 pm
- Place: 4274 Chamberlin
- Speaker: Art Schmaltz, Prairie State College
- Abstract: Language evolution has been deemed the hardest problem in science. Part of the problem resides in discovering the prior evolved biological system upon which human language has scaffolded itself. Efforts to locate which simpler features evolved into language have met with problems. The resolution to the dilemma of language evolution may involve a Copernican leap. Instead of a theoretical trajectory going from a simple evolved system to a complex system, the opposite strategy might resolve the problem. Neuroscience has discovered the enormous amount of brain power required for language functioning. The only brain function more complex, involving more information processing in the human brain, occurs during REM dreaming. Dreaming is a biologically hardwired brain function that is in some ways more complex than waking linguistic functioning. Dreaming is also phylogenetically older than human language. Dreaming as the birthplace of language is throughly consistent with Darwinian evolutionary theory.
- Host: Sprott
- Theory Seminar (High Energy/Cosmology)
- Title to be announced
- Time: 4:00 pm - 5:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Yang Bai, SLAC
Wednesday, February 29th, 2012
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Tests of Lorentz Invariance with Neutrinos
- Time: 11:00 am
- Place: 5280 Chamberlin Hall
- Speaker: Teppei Katori, MIT
- Abstract: Lorentz violation is a predicted signal from Planck scale physics. Since neutrino oscillation experiments are natural interferometers, they may be sensitive to small space-time effect, such as Lorentz violation through their sidereal time dependence. The sensitivity is comparable to precision optical measurements (10E-19 GeV). Thus, neutrino oscillations may be the first place where we see Lorentz and CPT violation.<br>
<br>
Recently the MiniBooNE neutrino oscillation experiment published electron and anti-electron neutrino appearance oscillation results that cannot be understood within the accepted three-massive-neutrinos oscillation model. In this talk, I will introduce Lorentz violation and Lorentz violating neutrino oscillations. Then, I examine whether the MiniBooNE data may be explained through a Lorentz violation model. Finally, I discuss how these results and other Lorentz violation tests address the "superluminal neutrino observation" from OPERA experiment.<br>
- Host: Halzen
Thursday, March 1st, 2012
- R. G. Herb Condensed Matter Seminar
- Challenges in Quantum Computer Architecture
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Ken Brown, Schools of Chemistry & Biochemistry; Computational Science & Engineering; and Physics, Georgia Institute of Technology
- Abstract: The development of a large-scale quantum computer faces two challenges: faulty hardware components and the inability to copy quantum information. Despite the no-cloning theorem, it is possible to use fault-tolerant quantum error correction techniques to generate arbitrarily reliable logical components. In the context of an algorithm, the inability to copy quantum information requires that a block of data that needs to interact with two other data blocks must be transported first from one block and then to the other. Although it is widely appreciated that the bulk of resources in a scalable quantum computers will be devoted to error correction, the significant cost of communication during the computation is only now being understood [1]. This can have a dramatic effect on the utility of a quantum computer as a simulator of other quantum systems [2].
I will discuss methods for estimating the communication cost on two distinct hardware layouts for ion trap quantum computation in the context of concatenated error correcting codes. In the first hardware layout, the ions are held in multiple zones and communications is performed by physically shuttling ions between zones [3]. The second hardware layout uses photons to create entangled ions in distant traps by the process of heralded entanglement [4]. These entangled ions are then used as teleportation channels to transfer information. I will compare possible architectures for arranging these systems on the logical level. Finally, I will briefly describe how these same architectural ideas can be applied in the setting of topological error correction.
[1] M.G. Whitney, N. Isailovic, Y. Patel and J. Kubiatowicz, A fault tolerant, area efficient architecture for Shor's factoring algorithm, Proc. of the 39th Annual Intl. Symp. on Computer Architecture ( ISCA), 383 (2009).
[2]C. R. Clark, T. S. Metodi, S. D. Gasster, and K. R. Brown, Resource requirements for fault-tolerant quantum simulation: the transverse Ising model ground state, Phys. Rev. A 79, 062314 (2009).
[3] D. Kielpinski, C. Monroe & D. J. Wineland, Architecture for a large-scale ion-trap quantum computer, Nature 417, 709 (2002).
[4] L.-M. Duan and C. Monroe, Quantum networks with trapped ions ,Rev. Mod. Phys. 82, 1209 (2010).
- Host: Saffman
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Rotation and turbulence in laboratory and astrophysical systems
- Time: 12:00 pm
- Place: 4274 Chamberlin
- Speaker: Eric Edlund, Princeton Plasma Physics Laboratory
- Astronomy Colloquium
- Secular Chaos: Formation of Hot Jupiters and the organization of Planetary Systems
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall
- Speaker: Yoram Lithwick, Northwestern University
- Abstract: In a planetary system with well-spaced planets, there is a nonlinear instability that can lead to chaotic behaviour. One of the planets can gradually become unstable, in which case its orbit becomes highly eccentric. This "secular chaos" is known to be responsible for the eventual destabilization of Mercury in our own Solar System. Here I focus on systems with multiple giant planets. I show that after an extended period of eccentricity diffusion, the inner planet's pericentre can approach the star to within a few stellar radii. Strong tidal interactions with the star then pull the planet inward, creating a hot Jupiter. In contrast to other proposed channels for the production of hot Jupiters, such a scenario (which I term "secular migration") explains a range of observations: the pile-up of hot Jupiters at 3-day orbital periods, the fact that hot Jupiters are in general less massive than other RV planets, that they may have misaligned inclinations with respect to stellar spin, and that they have few easily detectable companions (but may have giant companions in distant orbits). I will also show that if an unstable planet escapes the influence of the other planets, the remaining planetary system becomes increasingly stable. This may explain the stable architecture of observed systems.
- Host: Professor Lazarian
Friday, March 2nd, 2012
- Theory Seminar (High Energy/Cosmology)
- Title to be announced
- Time: 2:00 pm - 3:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Liam Fitzpatrick, Stanford University
- Physics Department Colloquium
- Particle Astrophysics with Space- and Ground-Based Telescopes
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Reshmi Mukherjee, Barnard College & Columbia University
- Abstract: Very-high-energy (VHE) gamma-ray astrophysics has emerged as an exciting and vital field, with major discoveries made through experiments in space and on the ground. In space, at energies above 100 MeV, the Fermi satellite studies some of the most violent processes in the Universe, and explores nature's highest energy accelerators. At energies greater than about 100 GeV, gamma-ray astronomy can be carried out using ground-based telescopes, such as the VERITAS Observatory, which detects the Cherenkov light from air-showers initiated by gamma rays impacting the upper atmosphere. VERITAS has discovered many astrophysical sources of VHE gamma rays. Some of the most exciting sources detected are blazars, with highly variable fluxes. The combination of high luminosities and time variations seen in the data indicates that gamma-rays are an important component of the relativistic jet thought to characterize blazars. This talk will outline the scientific motivation for VHE gamma-ray astronomy, describe the techniques involved, and survey the astrophysics of the extreme Universe, as revealed by observations made with gamma rays.
- Host: Westerhoff