Physics and Astronomy News

The Spring 2012 term is now underway, which means a new spring colloquium series. Come to the Department on Thursdays for a free lunch and a fascinating set of talks.

The Winter 2012 Physics and Astronomy Colloquium series will begin on Thursday, January 12, at 12:40 pm (lunch at 12:15), with a talk by David LeSage from Harvard. The full colloquium schedule is online.

Title: A Sound Way to Measure Nanostructures: Ultrafast Optics and Picosecond Ultrasonics

Speaker: Brian Daly, Vassar College

Abstract: We can take it for granted that progress in nanoscale science and technology in the coming decades will depend heavily on imaging and sensing methods with nanometer resolution. A number of established techniques can provide us with this resolution (e.g. electron microscopy, atomic force microscopy) but these are restricted to objects on or very near the surface of a sample. A wide range of nanostructures are currently under development across the spectrum of the sciences, and in many cases these structures come in the form of multi-layered stacks. As such, a method for the study of buried nanostructures and films is required.

One solution to this problem is to use ultrasound, which has been successful in medical and industrial fields for imaging with optimum resolution in the range of 10’s to 100’s of micrometers. In order to obtain nanometer scale resolution, we must use waves that have a much shorter wavelength (higher frequency) than traditional ultrasound. To do this, we use one of the most versatile tools of the quantum mechanical age, the ultrafast laser. An ultrafast laser produces pulses of light that are shorter than 1 picosecond, and when these pulses are absorbed by a solid layer, they generate extremely high frequency sound waves: what we like to call “Picosecond Ultrasonics.”

In this presentation I will give an overview of the way in which we use light to generate and detect high-frequency ultrasound in solid samples. I will also describe a companion technique for measuring thermal properties of nanoscale films known as Time-Domain Thermoreflectance

As always, lunch will be provided at 12:20 in Room N304, and all are welcome. The full schedule for the Fall term Physics and Astronomy Colloquium Series is here.

Alex Safiq ‘14 explaining her research project.

Vaishali Parkash ‘14 explaining her research project

Students and faculty at the Summer Research Poster Session.

The N^th Annual Summer Student Poster Session will be held this Thursday, September 15. Students who did summer research projects either on campus or at other institutions will give posters on their work in the halls of the Department of Physics and Astronomy, beginning at 12:20 pm. As always, lunch will be provided at 12:20 in Room N304, and all are welcome to come hear about the exciting activities of our students.

The poster session is also the traditional kick-off for the Fall term Physics and Astronomy Colloquium Series, the full schedule for which is here.

The Spring 2011 Physics and Astronomy colloquium series is now underway. The complete schedule is on-line. Talks will be in Room N304 of the Science and Engineering Center at 12:40 pm, with pizza and soda provided at 12:20 for people attending the colloquium. All are welcome.

Speaker: Ann Martin, Cornell University

Title: ALFALFA and the Hunt for Extreme-Mass Galaxies

Abstract: The ongoing Arecibo Legacy Fast ALFA (ALFALFA) survey is using the Arecibo Observatory to make a census of neutral hydrogen gas in ~ 30,000 nearby galaxies. This method is efficient at finding very low mass, very faint galaxies as well as distant, rare high-mass galaxies. The statistical distributions of gas-rich galaxies in the local Universe will reveal relationships between galaxies’ stellar properties, star formation histories, gas masses, and environment, helping us to untangle galaxy evolution. I will describe ongoing projects that challenge our current understanding of both very small and very large galaxies. I will discuss two statistics, the neutral hydrogen mass function and the correlation function, and how they reflect the cosmological implications of the characteristics of the ALFALFA sample.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Winter 2011 colloquium schedule.

Speaker: Jason E. Sanabia ‘96, Ph.D., President & CEO Raith USA, Inc.

Title The Roles of High and Low Energy Electrons in Nanofabrication

Abstract In his 1959 speech entitled There’s Plenty of Room at the Bottom, Richard Feynman asked “Why cannot we write the entire 24 volumes the Encyclopedia Brittanica on the head of a pin?” After explaining how it was possible, Richard Feynman next asked “How do we write it?” and then hypothesized “We can reverse the lenses of the electron microscope.” Toward the end of his speech, Richard Feynman offered a price of $1,000 to “the first guy who can take the information on the page of a book, and put it on an area 1/25,000 smaller in linear scale, in such manner that it can be read by an electron microscope.” In 1985, Richard Feynman mailed a check for $1000 to Tom Newman, then a graduate student in R. Fabian W. Pease’s group at Stanford University, who used electron beam lithography to write the opening page of Dickens’ A Tale of Two Cities at a scale of nanometers.

Today, 50 years since Richard Feynman launched the field of nanotechnology, electron beam lithography is a critical facility for the world’s research in nanotechnology. Device physics research (graphene and spintronics), materials science (bit patterned media), electrical engineering (transistors), mechanical engineering (nanoelectromechanical systems, NEMS), optical engineering (waveguides and photonic structures), and biophysics (single molecule detection) are examples of today’s active fields of research that benefit from electron beam lithography facilities. But why cannot electron beam lithography do everything? Why is it difficult to control matter below 10 nm with electron beam lithography? What prevents the manufacture of computer chips using electron beam lithography? I will introduce the basic concepts of electron beam lithography, with particular emphasis on the roles of the high and low energy electrons. Within this framework, I will discuss today’s challenges that limit the application of electron beam lithography.

Joint colloquium with Chemistry Department

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Winter 2011 colloquium schedule.

Instead of a Physics and Astronomy colloquium this Thursday, January 27th, we will be having a departmental pot-luck luncheon at the usual colloquium time of 12:40. If you’re around, stop by the department office to sample the cooking of your favorite professors.

Speaker: Prof. Chad Orzel, Union

Title: “Talking to My Dog About Science: Why Public Communication Matters, and How Social Media Can Help”

Abstract:: At a time when the primary challenges facing the world are scientific in nature– pandemic disease, global climate change, green energy and technology– it is more important than ever that the general public have some understanding of and appreciation for science. At the same time, polls show that public understanding of science lags far behind the necessary level, and well-funded media operations attempting to sow doubt about issues like climate change have had a major negative impact. In this talk, I will discuss some of the problems with communicating science to the general public, and discuss the new opportunities for public communication afforded by Internet technologies.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Winter 2011 colloquium schedule.

Speaker: Jason Slaunwhite ‘04, CERN

Title: Exploring the Standard Model at the Large Hadron Collider

Abstract: The Large Hardron Collider (LHC) is one of the world’s largest scientific experiments. It aspires to answer some of the most exciting questions in particle physics today. In this talk, I will discuss the current model of particle physics and describe some of the outstanding questions. I will explain how we use the LHC answer these questions and highlight some recent results.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Winter 2011 colloquium schedule.

Speaker:Dr. William Ostendorff, Nuclear Regulatory Commission

Title: Principles of Physics for Nuclear Power

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Fall 2010 colloquium schedule.

Speaker: Prof. John Cummings, Siena College

Title: Neutrino Physics and The Dayabay Experiment

Abstract: There has been a resurgence in interest in neutrino physics in the last 10 years. The observations of the Super-Kamiokande Experiment in 1998 indicated the “oscillation” of one flavor neutrino into another. Several experiments, now running or soon to begin, are attempting to map out the details of the neutrino mixing responsible for this oscillation phenomena. I will present a (brief) history of our understanding of the neutrino, and describe the phenomena of neutrino oscillations and what we can learn from them. Finally, I’ll describe the Dayabay experiment and it’s goals.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Fall 2010 colloquium schedule.

Speaker: Prof. Charles Freeman, SUNY Geneseo

Title: The Physics of Baseball

Abstract: Baseball is a particularly interesting game for a physicist to study. What makes a curve ball curve? How much farther does the ball really travel at Coors Field in Denver than at Citi Field in New York? Why do left handed pitchers have more success against left handed batters (and right handed pitchers have more success against right handed batters)? What is the difference between a two-seam and a four-seam fastball? How do you throw a split-fingered fastball, anyway? An ex-pitcher and current physicist sheds some light on these questions and discusses some other interesting physics at work in our national pastime. Feel free to bring your glove — you just might catch a souvenir.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Fall 2010 colloquium schedule.

Speaker: Prof. Rebecca Surman

Title: Astrophysical Alchemy: Creating the Heaviest Elements Within the Galaxy’s Biggest Explosions

Abstract: While the origins of the light (hydrogen, helium) and intermediate mass (carbon through iron) elements found in our solar system are well understood, we still don’t know where roughly half of the elements heavier than iron were made. From the solar system abundance pattern of these nuclei, we can tell they were synthesized in conditions of high temperature and free neutron density. However, where these extreme conditions are found astrophysically is still uncertain. Here we will discuss aspects of heavy element synthesis in two potential astrophysical sites: the neutrino-driven wind of core-collapse supernovae and hot outflows from compact object mergers.

As always, the colloquium will be at 12:40 in Room N304, with pizza and soda available at 12:20 for those attending the talk. For details of future colloquia, see the Fall 2010 colloquium schedule.

Speaker: Petros Thomas

Title: Carbonaceous Contamination on Extreme Ultraviolet Lithography Mirrors Due to Different Wavelengths of Light

Abstract: Extreme Ultraviolet Lithography (EUVL) is one the leading candidates as the next generation of lithographic technology for the semiconductor industry. One of the challenges of EUVL is the carbonaceous contamination of the multilayer EUV mirrors in the tool which reduces the reflectivity of the mirrors in the desired wavelength range. Carbonaceous contamination on optical surfaces due to light in hydrocarbon environment is a major problem in different applications such as synchrotron beam lines, astronomy telescopes, and recently in EUV lithography. Although the problem has been around for a long time, the basic mechanism of the contamination is still not fully understood. The contamination is localized to the region of the surface exposed to light in the presence of hydrocarbons. The hydrocarbons dissociate and leave carbonaceous film in the exposed region of the surface. Whether the dissociation of the hydrocarbons is caused by the incoming photons of the light or secondary electrons from the surface is not well known.

Using a Xe-plasma source which emits not only the desired wavelength near 13.5 nm (EUV light) but a wide range of out-of-band (OOB) wavelengths extending as far as the visible region, we studied the carbonaceous contamination rates of different wavelength regions. We have measured the wavelength dependence of carbon contamination on a Ru-capped mirror. These results are compared to contamination rates on TiO₂ and ZrO₂ capping layers.

Students and faculty gathered in the department on Thursday, September 16th for the fourth annual Summer Research Student Poster Session, with 18 students presenting 16 posters on their research activities over the summer.

Watch this space for more details about the students and their projects.

The annual Summer Research Poster session will be held Thursday, September 16th in the Department, from 12:20 pm to 1:40 pm. Pizza and soda will be available in room N304 for people attending the poster session. You can check out the list of presenters and poster titles to get an idea of the range of activities.

This is the official kick-off of the fall colloquium season. Come see the fascinating things our students did on their summer vacations.

The colloquium coordinator for 2010-2011 is Prof. Jon Marr, and the complete Fall schedule is here.

Colloquia are held on Thursdays at 12:40pm in Room N304 of the Science and Engineering Center, unless otherwise noted. Pizza and soda are provided at 12:15. All are welcome.

14-Jan Dr. Harry Ringermacher, General Electric Global Research Center, Why does the Hubble Classification of Spiral Galaxies Correlate Poorly with their Arm Angle-of-Pitch ?

Since Hubble himself classified spiral galaxies according to arm sweep and bulge size (Sa, Sb and Sc types representing increasing sweep with decreasing bulge), one might naturally expect that the carefully measured angle-of-pitch of arms in spiral galaxies should correlate very well with Hubble Type. In fact, ever since Danvers plotted arm-pitch vs Hubble Type in 1942 to recent measurements by Kennicutt and Seigar, little or no correlation has been found. We prove there are two root causes: 1) misclassification of galaxies, and, most critically; (2) the assumption that “average pitch”, used by all astronomers in measuring galaxy pitch, is a good correlation parameter. We introduce a new formula that describes the natural pitch variation of all spiral galaxies dependent only on a single “pitch-parameter”. The pitch parameter of our formula, for the first time, produces an excellent correlation to Hubble Type in a study of 21 galaxies. Representative examples of fitted galaxies will be shown.

7-Jan Dr. Sarah Demers, Yale University, Hunting for New Physics at the LHC

CERN’s Large Hadron Collider (LHC) brings a new energy frontier to particle physics with the potential for discoveries of new physics. The thousands of physicists collaborating on the LHC experiments are in the final stages of preparation for the 2010 run and are analyzing the collisions that began in December, 2009. In this talk I will introduce the LHC and the ATLAS experiment and discuss some of the ways in which we hope to add to our understanding of the fundamental particles and forces in nature.

4-Feb Mark Kostuk Using Chaotic Synchronization for Nonlinear State and Parameter Estimation: Theory and Applications from Bird-Brains to Barotropic Vorticity.

Nonlinear systems abound in nature; unfortunately when studying such systems it is usually only possible to measure an incomplete portion of its dynamical state. Due to the possible existence of chaos in the dynamics, this presents the researcher with a problem if they have a representative model of the system and wish to use these measurements to uncover information about any of its unknown parameters. Alternatively, what if the exact underlying physics of the system are known and one would like to predict its future behavior; this is only possible if one has complete knowledge of its current state. In this talk I will discuss this general problem, why standard estimation techniques may fail, and how we use the phenomena of chaotic synchronization -in the form of an optimization problem- to gain a complete estimate of the state and any unknown parameters of a nonlinear system from incomplete data. I will demonstrate its successful application to a wide variety of nonlinear problems, from neuron models of the vocal center of the zebra finch to simplified fluid-dynamics models of the ocean. In addition, this method can be used to filter noisy measurements, and to provide a measure with which to choose between competing models. Crucially for large problems, such as weather forecasting, it is also possible to determine the number of measurements that are necessary for such estimations to be successful.

11-Feb Matt Martin ‘06 RPI Title TBA

4-Mar Alex Handin ‘10 Senior Thesis Research Presentation