Relevant Physics and Astronomy Colloquia
Short ListMarch 5, 2013 Andrei
Nomerotski, Brookhaven National Lab
March 22, 2011 Angela
Kelly, Lehman College, CUNY
February 22, 2011 Howard
Schneider, Stony Brook
November 9, 2010 Dominik
Schneble, Stony
Brook
November 2, 2010 Hal
Metcalf, Stony Brook
Oct. 12, 2010 Gordon Cates, Virigina
October 27, 2009 Grover
Swartzlander, RIT
October 6, 2009 Kiko Galvez, Colgate University
September 22, 2009 Steve
Smith, Stony Brook University
March 10, 2009 Miles Padgett,
University of Glasgow
February 3, 2009 John
Marburger, Stony Brook
February 10, 2009 Jim Simons, Renaissance Technologies Corporation
November 25, 2008 David
DeMille, Yale
University
September 23, 2008 Anand Sivaramakrishnan, American Museum of
Natural History
March 11, 2008 Joe
Eberly, University of Rochester
Februrary 19, 2008 Hal
Metcalf, Stony Brook
November 13, 2007 Pierre Meystre, Optical Sciences Center,
University of Arizona
October 30, 2007 Paul Brumer,
University of Toronto
October 23, 2007 Thomas Weinacht, Stony
Brook
February 27, 2007 Marusa Bradac, KIPAC Institute SLAC
October 24, 2006 Bill Phillips, University of Maryland
February 7, 2006 Uwe Bergmann, Stanford Synchrotron Radiation
Laboratory February 8, 2005 Michael Berry, Bristol Detailed viewMarch 5, 2013 Andrei
Nomerotski, Brookhaven National Lab
We will review recent advances in science enabled by rapid progress in time resolved imaging. Examples will include two extremes: imaging mass spectrometry with demand of 1 ns resolution and Large Synoptic Survey Telescope, which will be imaging half of the Universe every three days for ten years unveiling mysteries of Dark Energy and Dark Matter. March 22, 2011 Angela
Kelly, Lehman College, CUNY
High school physics is a gateway course for post-secondary study in STEM related fields, and an important component in the formation of students’ scientific literacy. Although the percentage of students taking high school physics has increased in recent years to a high of 37% in 2009 (AIP, 2010), access and enrollment have been unevenly distributed and have been influenced by a variety of factors. The presentation will focus on three aspects of physics accessibility in secondary schools: 1) quantitative data illustrating the status of physics availability in the U.S., New York State, and New York City, 2) qualitative data outlining the impacts of standardized testing on physics course-taking in several states, and 3) the unintended consequences of select districtand state-based reform initiatives on physics access and enrollment. First, the limitations of urban secondary physics programs will be discussed through data collected in New York City, where physics course offerings have been limited and certain organizational variables have correlated to whether schools offer physics. Secondly, standardized testing content (Regents, FCAT, PSAE, etc.) has often marginalized physics in the secondary science sequence. Finally, teachers and administrators have shared their views of recent reform initiatives in their districts. I will present data from interviews and focus groups where key players have reflected on various reform structures and how they have been implemented and evaluated. Such policies have also influenced whether physics has been offered, and whether students have elected to take it. Future research related to student participation in physics will also be discussed. Howard
Schneider, Stony Brook
In survey after survey, most Americans say they are interested in science, value its contributions and respect scientists. But the surveys also show that many Americans do not understand or accept scientific evidence and conclusions in areas like evolution, climate change, vaccination or the risk of radiation, and view investment in basic research as misguided. Stony Brook has taken the lead in creating an innovative new program in training future and current scientists to communicate more effectively with the public, the press, funders and colleagues across disciplines. Already, more than 200 scientists and graduate students at SBU, Brookhaven Lab and Cold Spring Harbor have participated in the program—which includes workshops ranging from writing for the public to improvisational theater games directed by Alan Alda. Howie Schneider, the dean of the School of Journalism, will report on the results so far, plans to expand the program for all science graduate students and faculty, and discuss the contributions of contemporary physicists and astronomers in “breaking the communications barrier.” November 9, 2010 Dominik
Schneble, Stony
Brook
Quantum gases in optical lattices allow for fundamental studies in atomic and condensed-matter physics, including strongly-correlated many-body systems. My talk will focus on possibilities with atomic mixtures (derived from a Bose-Einstein condensate) in lattices whose depth can be independently controlled for each component. In three recent experiments, we have explored novel features arising from interactions in the mixture: collinear atomic four-wave mixing, polaronic shifts in the strongly correlated regime, and scattering from crystalline atomic structures. My talk will conclude with prospects for future activities. November 2, 2010 Hal
Metcalf, Stony Brook
Optical forces, or light pressure, was derived by Maxwell and survived intact through both relativity and quantum optics simply because E = pc. It was studied in the 1908 Ph.D. thesis of Peter Debye on comet tails. The optical forces used for laser cooling require rather special properties, namely, velocity dependence so that when atoms are slowed to some selectable speed the force vanishes instead of reversing their direction and accelerating them again. This velocity dependence is often implemented through the Doppler shift: the light is tuned so that atoms would need to be Doppler-shifted into resonance with it. Atoms at rest would be too far out of resonance to interact strongly. Since this is the year of LaserFest, it's important to discuss why such cooling forces need to use laser light. The temporal coherence of laser light enables precise enough tuning and stability to control Doppler shifts on the scale of the natural width γ. My role in laser cooling began in the late 1970's in a conversation with Bill Phillips while he was still a graduate student at MIT. When he explained the ideas to me, I responded that it simply couldn't work because shining laser light on something can only add energy and heat it up. I thought that was the end of it until it occurred to me that making ice cubes requires the refrigerator to be plugged in, and that its mechanism only served to redistribute heat energy. We need to think about laser cooling in terms of momentum (force), energy, and thermodynamics (entropy). Gordon Cates, Virigina
Laser polarized He-3 provides a powerful tool for both subatomic physics as well as medical imaging. Recent electron scattering measurements using a polarized he-3 target at JLab, in Newport News, Va, have provided what might loosely be called the highest resolution "snapshot" of the neutron to date through measurements of the electric form factor. In medical imaging, polarized He-3 has long provided the highest resolution images of the gas space of the lungs, work that has its origins in a Princeton/Stony Brook collaboration from the mid 1990's. Now He-3 can be used to provide high-resolution dynamic studies of lung function, as well as regional mapping of microscopic changes in lung structure. The next generation of studies in both subatomic physics and medical imaging continue to provide the potential for exciting new directions. October 27, 2009 Grover
Swartzlander, RIT
I will show how light can be focused by using only polarization elements. Surprisingly, both the amplitude and phase of a beam may be arbitrarily controlled with computer-generated elements called vectographs, combined with a quarter wave retarder. Vectographs are non-uniformly dyed polarizers that have been used for years to produced gorgeous colorful stereoscopic images (and even a few movies). This talk will discuss our recent fabrications of the first vectographic lens and vectographic vortex. This novel approach to beam shaping and wavefront control may one day rival holography. Kiko Galvez, Colgate University
Recent technological advances have allowed numerous fundamental tests of quantum mechanics via violations of Bell's inequalities of various forms and situations. The use of quantal systems to encode and manipulate information in a non-classical way has led to the rise of a new interdisciplinary field of quantum information. At the heart of both is quantum interference. This rise to prominence has also led us to reconsider how we introduce quantum mechanics in instruction, moving away from "shut up and calculate" to measuring violations of Bell's inequalities as an undergraduate lab. At the colloquium I will present several experiments on quantum interference of light with the thread of reinventing how to introduce quantum mechanics even to first year students, but also understanding the more sophisticated role that photons play in discovering new ways in which quantum mechanics can be implemented for quantum information. September 22, 2009 Steve
Smith, Stony Brook University
Rhodopsin is a highly specialized G protein-coupled receptor (GPCR) that is activated by the rapid photochemical isomerization of its covalently bound 11-cis retinal chromophore, aka vitamin A. Absorption of light results in the cis-to-trans conversion of the retinal along a torsional coordinate in the electronic excited state of molecule in less than ~200 femtoseconds. The rapid structural change in the retinal leads to steric strain in the receptor, which is released on the timescale of milliseconds and causes a conformational change in the receptor. I will describe structural studies using Nuclear Magnetic Resonance (NMR) spectroscopy to describe how this visual receptor transduces light into a chemical and biological signal. March 10, 2009 Miles Padgett,
University of Glasgow
It is 15 years since Les Allen et al. recognised that light beams could be made in the laboratory which carried an Orbital Angular Momentum. Since that time much of my own group's work has been the exploration of this phenomenon, ranging from optical spanners and rotational frequency shifts to an angular form of Heisenberg's uncertainty principle. This lecture will, however, concentrate upon two of our current interests namely the role that angular momentum plays in the 3D structure of random speckle and most recently the quantum entanglement of spatial modes in parametric down-conversion. John
Marburger, Stony Brook
In his famous 1927 paper Heisenberg derived the product of uncertainties in position and momentum for a Gaussian wave packet, and gave physical arguments for more general situations. Only later, in lectures at Chicago University, did Heisenberg derive the rigorous inequality we associate today with uncertainty relations. He cited a work by E.H. Kennard in connection with his derivation, and historians credit Kennard with the first proof. In 2007 I compared Heisenberg's Chicago proof with Kennard's and found they are completely different and that Kennard's version is fatally flawed. Probably the familiar proof based on Schwarz's inequality is due to Pauli. Heisenberg's intention for the uncertainty relations is obsolete, but they and their subsequent refinements are relevant to non-classical 'squeezed' states of light which are shifted ground states of the general linear quantum system. February 10, 2009 Jim Simons, Renaissance Technologies Corporation
November 25, 2008 David
DeMille, Yale
University
Our group has undertaken a program to apply the techniques of modern atomic physics--cooling, trapping, and ultra-precise control and measurement--to the more complex system of diatomic molecules. The vibrational and rotational degree of freedom in molecules makes these systems qualitatively different than atoms. Control over these properties is enabling new and powerful ways to attack a broad range of problems, ranging all the way from particle physics and cosmology to quantum information processing and quantum chemistry. This talk will give an overview of the field, along with some specific examples of our recent work. September 23, 2008 Anand Sivaramakrishnan, American Museum of
Natural History
Extending particular frontiers of instrumentation can result in major advances in astronomical understanding. The study of planet and star formation is in the midst of such an expansion now. Bright speckles around a stellar image swamp any faint planetary companion's signal. This speckle noise results from tiny residual errors in the almost perfect optics of today's telescopes. Instruments dedicated to direct detection and characterization of extrasolar planets must combat this speckle noise to deliver science. I will explain the imaging problem, show how adaptive optics coronagraphy reduces speckle noise, and present some of our ground-breaking coronagraphic results. We recently captured the first image of a solar-system scale planet-forming disk around a young star, opening up search spaces inaccessible to even the Hubble Space Telescope. I will also describe a new approach, the non-redundant masking of a telescope aperture, which eliminates speckle noise. With such aperture masking we can peer closer to a star than has hitherto been possible. We hope to implement this technique on NASA's flagship mission, the 6.5-m IR James Webb Space Telescope, scheduled for launch in 2013. March 11, 2008 Joe
Eberly, University of Rochester
The invention of the two-photon Clauser interferometer signalled a completely new domain of spectroscopy. It allowed direct experimental demonstration for the first time of non-local, non-realist phenomena in physics. I will describe an idealized version of this interferometer and various phenomena at the interface between classical and quantum physics that are related to it (e.g. Schroedinger's Cat). An indirect consequence is that decay to steady state is not always what we were taught. Recent experiments on photons and atoms demonstrate the difference between local decay and non-local decay of entangled quantum systems. Even when decay of a system is locally smoothly asymptotic, non-local entanglement may be non-smooth and disappear discontinuously. This "sudden death" constitutes a strongly counterintuitive trait of entanglement, confirming earlier predictions, but not yet really explained. Februrary 19, 2008 Hal
Metcalf, Stony Brook
Laser cooling is usually viewed as compression in velocity space by a velocity-dependent force but such forces do not conserve energy. A proper description must include the light field that absorbs the energy from spontaneous emission, so the light field must be part of the system. It is usually presumed that spontaneous emission is necessary to remove the entropy lost by the atoms, and a closer look suggests that this happens by redistributing the light among the empty states of the radiation field. But the laser beams themselves have sufficient entropy capacity so that stimulated emission can do precisely the same thing. Thus the system doesn’t undergo a loss of entropy but merely its redistribution among its parts of the system. The entropy in the light field is not dissipated until the outgoing beams hit the walls in a non-conservative, irreversible process. November 13, 2007 Pierre Meystre, Optical Sciences Center,
University of Arizona
The observation of quantum dynamics in truly macroscopic objects appears increasingly feasible as a result of recent experimental advances thatinclude novel cooling techniques and progress in nanofabrication. This is an exciting prospect, as it would enable us to explore the quantum-classical boundary as well as to test quantum mechanics in an entirely new regime. The implementation of characteristically quantum mechanical phenomena at a macroscopic scale also promises technological benefits for areas from quantum measurement to the interferometric detection of gravitational waves and to atomic force microscopy. A promising route to these objectives is through the use of optomechanical systems, particularly optical cavities where the support of one of the mirrors is a nanoscale cantilever. The talk will review recent developments in the optical cooling of these moving mirrors and discuss the prospects for reaching their quantum mechanical ground state of vibration. Future directions, including the realization of ro-vibrational quantum entanglement in these systems, will also be touched upon. October 30, 2007 Paul Brumer,
University of Toronto
Coherent Control offers a powerful approach to the control of atomic and molecular processes. By manipulating quantum interference effects, primarily through laser excitation, control over multipath molecular processes can be achieved. This lecture will provide an introductory overview of coherent control, followed by a summary of new developments in the control of both bound state and scattering processes. October 23, 2007 Thomas Weinacht, Stony
Brook
Ultrafast laser pulses can be used to initiate and capture atomic and molecular motion in real time. Shaping these pulses allows us to control the dynamics we observe. I will discuss some experiments that follow bond breaking and formation driven by an ultrafast laser pulse. I will also discuss an experiment where a shaped ultrafast laser pulse is used to control lasing of an atomic ensemble. I will conclude with some future prospects and goals. February 27, 2007 Marusa Bradac, KIPAC Institute SLAC
The cluster of galaxies 1E0657-56 has been the subject of intense ongoing research in the last few years. This system is remarkably well-suited to addressing outstanding issues in both cosmology and fundamental physics. It is one of the hottest and most luminous X-ray clusters known and is unique in being a major supersonic cluster merger occurring nearly in the plane of the sky, earning it the nickname "the Bullet Cluster". In this talk I will present our measurements of the composition of this system, show the evidence for existence of dark matter, and describe limits that can be placed on the intrinsic properties of dark matter particles. In addition, I will explain how this cluster offers a serious challenge to MOdified Newtonian Dynamics (MOND) theories. Bill Phillips, University of Maryland
An atomic-gas Bose-Einstein Condensate, placed in the periodic light-shift potential of an optical standing wave, exhibits many features that are similar to the familiar problem of electrons moving in the periodic potential of a solid-state crystal lattice. Among the differences are that the BEC represents a wavefunction whose coherence extends over the entire lattice, with what is essentially a single quasi momentum and that the lattice potential can be turned on and off or accelerated through space. Experiments that are not easily done with solids are often straightforward with optical lattices, sometimes with surprising results. February 7, 2006 Uwe Bergmann, Stanford Synchrotron Radiation
Laboratory Archimedes (287 - 212 BC) is considered one of the most brilliant thinkers of all times. The 10th century parchment document known as the Archimedes Palimpsest is the unique source for two of the Greek's treatises - the Stomachion, and The Method of Mechanical Theorems. It is also the only source for On Floating Bodies in Greek. The privately owned palimpsest is the subject of an integrated campaign of conservation, imaging, and scholarship being undertaken at the Walters Art Museum in Baltimore. Much of the text has been imaged by various optical techniques, but even today significant gaps remain in our knowledge of the text of Archimedes, while texts by other authors - potentially of major significance - remain yet unread. A breakthrough in uncovering the remaining unread text has recently been achieved. Using x-ray fluorescence imaging at the iron K-edge, it was possible to uncover text from faint traces of the partly erased iron gall ink. The x-ray image revealed Archimedes text hidden underneath 20th century gold forgeries and covered by 12th century biblical writings. Some of this text has not been read since more than a millennium. Please join me in a fascinating journey of a 1000 year old parchment from its origin in the Mediterranean city of Constantinople to an x-ray beamline at the Stanford Synchrotron Radiation Laboratory. February 8, 2005 Michael Berry, Bristol |