October 2008

The Force
Department of Physics and Astronomy
Franklin and Marshall College
Fall, 2008
"MAY THE FORCE BE WITH YOU"
CLAIRE BOOTH LUCE AWARD
RECIPIENT
Elizabeth Bushong ʼ10 is the first
recipient of the Claire Booth Luce
Award. Clare Boothe Luce, the
widow of Henry R. Luce, was a
playwright, journalist, U.S.
Ambassador to Italy and the first
woman elected to Congress from
Connecticut. In her bequest, she
established a scholarship to
encourage American women to
pursue professions in math and
sciences.
"Iʼve always been an inquisitive
person," Bushong said. "Physics
gives me a chance to question why
and how things happen in the world."
Elizabeth Bushong in the Physics
Lab
When she first came to Franklin &
Marshall College, Bushong also
studied chemistry. She showed
promise in both and was asked to
join a select few to work in the
chemistry lab before her first year as
a Moore Mentor. Before her
sophomore year, she stayed over the
summer as a Hackman scholar in
chemistry. However, by the end of
her sophomore year she had made
her choice. Physics won her over!
After she graduates from Franklin &
Marshall Bushong plans to go to
graduate school and perhaps get a
doctorate.
The Clare Boothe Luce Award is a
program of the Henry Luce
Foundation. For more information on
the award visit www.hluce.org.
THREE ACHIEVE TENURE IN THE
PHYSICS AND ASTRONOMY
DEPARTMENT
We are pleased to announce that
three professors in the department
received tenure this past academic
year. Ken Krebs, Christie
Larochelle and Andrea Lommen
are now tenured members of the
department. All three started in the
department at about the same time
and, happily, all have been given
tenure and will remain at the college.
When asked for a reaction to the
good news Andrea Lommen replied,
(Tenure, continued on page 2)
The Force
Fall, 2008
(Tenure, continued from pg 1)
"It's a privilege to
be made a permanent part of this
extremely dedicated department. I
look forward to many more years of
service to the department and the
college."
Prof. Larochelle
said ""I have thoroughly enjoyed
being a part of the F&M community
for the last six years and I feel that it
is a privilege to be able to continue
my work with students here for years
to come."
Ken Krebs, smiling said,
"Woo Hoo!"
OUTREACH PROGRAM BEGUN
AT MC CASKEY HIGH SCHOOL
Ian Hagman ʼ11 and Laura
Perkowski ʼ11 and Professor
Andrea Lommen are at the
beginning stages of developing an
astronomy program at JP McCaskey
high school. Dan Weber ʼ06 is now
a math and physics teacher at
McCaskey and has been absolutely
essential to this program. Ian and
Laura will be showing McCaskey
students how to operate a telescope
in Bathurst, Australia via the web
and giving them follow-up work to do
with the images in the classroom
setting. Ian and Laura are also
developing materials that will be
used to introduce the concept of
gravitational waves to the students.
We look forward to giving you a
report of the first year of this program
in next yearʼs newsletter.
NEWS FROM THE P&A CLUB
This yearʼs F&M Physics and
Astronomy Club began this
academic year with the addition of 18
new members, bringing the total club
size to over 50 students. Our Fall
picnic was a huge success, not only
allowing new members to meet the
club and faculty, but also for
returning members to share stories
of their summer travels and
research.
Last springʼs big event was a trip to
the Laserdome. Members were
invited to relax and socialize with an
evening of Light Amplification by
Stimulated Emission of Radiation
(aka laser tag). It was such a
success that the club is considering
going again this fall. Aside from laser
(Club, Continued on pg 3)
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Fall, 2008
(Club, Continued from pg 2)
tag, the club also plans on
continuingits traditional movie nights,
as well as the addition of a spring trip
to Hershey Park to investigate the
"mechanics of rollercoasters".
This yearʼs officers include: Adam
Fusick (President), Arpita Roy,
(Vice President), Boyko Perfonov
(Treasurer), and Beth Bushong
(Secretary). The club is open to all
F&M students who have an interest
in Physics and Astronomy.
OBSERVING AT NURO
Froney Crawford traveled to
Arizona with Brian Burt '10, Chase
Morgan '08, and Arpita Roy '09
over spring break to observe several
variable stars in the Pleiades with
the NURO 31-inch telescope as part
of a continuing long-term study of
these stars. The observing was
successful, and photos from the trip,
including a hiking trip to the Devil's
Bridge in Sedona, are linked from the
F&M astronomy web site (just go to
the NURO link and look for a link to
the photos at the bottom of the
page).
KREBS RETURNS TO FRANCE
Only ten months after returning from
the International Sol-gel Conference
in Montpellier France, Associate
professor Ken Krebs returned to
France in July to present at the
International Conference on
Luminescence.
The conference was held in Lyon
from the 6th of July through the 11th.
This was the 15th meeting of the
conference, which brings together
scientist from industry and academia
from around the world to discuss
current research affecting
luminescent technologies.
Professor Krebs presented work
done with Zack Barninger ʻ07 on
the fluorescence decay of optical
impurity ions in nano-scale phosphor
particles. The work highlighted a new
theoretical approach to model how
optical impurities are distributed
within the nano-particle materials.
The meeting schedule highlighted
both oral and poster presentations
along with several social functions.
Krebs reports that the high-points of
conferences usually occur around
meal times, which in France are daily
special occasions.
CANADIAN PULSAR
CONFERENCE
Last summer Andrea Lommen and
Froney Crawford both attended a
pulsar conference at McGill
University, titled "40 Years of
Pulsars: Millisecond Pulsars,
Magnetars, and More", celebrating
the 40th anniversary of the discovery
of the first pulsar. Froney and
Andrea presented some of their
respective research work on pulsars,
and the proceedings from the
conference were published in an AIP
Conference Series volume.
The Force
Fall, 2008
CLICKERS GIVE EVERYONE A
VOICE
Andrea Lommen, Assistant
Professor of Physics and Astronomy
at Franklin & Marshall, teaches
courses with titles like Physics of
Movement and Stellar Astrophysics.
In 2008, Professor Lommen won a
NSF Grant (see page 6-8) to pursue
gravitational waves. This award
enables Professor Lommen and her
students unique opportunities to
study a fundamental problem in
physics and astronomy. In addition
to her research interests, Professor
Lommen has also embraced
technology in her teaching. She was
the first faculty member at the
College to use student response
systems, or "clickers," in the
classroom. Her interest in clickers
began as a search for a better way to
engage students actively during
class. During the Spring 2008
semester, Professor Lommen began
integrating clickers with her lectures
to collect data in real-time to
measure her students understanding
of her material
Students using clickers in class
She used the same lectures as she
always has, but using PowerPoint
along with the clickers this time, she
was able to engage her students
while at the same time analyzing
their responses immediately. "I have
noticed that no matter how great I
am at trying to elicit responses from
my students," Professor Lommen
said, "there are always the dominant
responders in class. Clickers give
everyone a voice."
Professor Lommen is encouraged by
the level of integration she was able
to achieve by using clickers and
other technologies in her teaching.
While she continues to deliver
powerful and meaningful lectures
about the solar system, she
continues to utilize technology to
augment her effectiveness as a
teacher. "The students realize they
have to put their thoughts on the line.
Because of that, they can
acknowledge what they do not
understand."
PERTURBATION TO ORBITAL
PERIODS DUE TO WEAK LONGRANGE
FORCES
During the summer of 2008,
Chelsea Meerbach and Professor
Adkins worked on a new approach
for detecting and placing bounds on
hypothetical weak long-range forces
in the solar system. They studied
the small but potentially detectable
effect of hypothetical new forces on
orbital periods. This work is being
continued this year in the context of
(Perterbation, continued on page
5)
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Fall, 2008
(Perterbation, continued from
page 4)
an Independent Study project for
Chelsea.
The standard model, currently the
best theory of fundamental physics,
cannot be a complete description of
nature. There is a great deal of
important physics that is not
addressed. Most importantly,
gravitation had no place in the
standard model. Also, the model
gives no internal explanations for the
many parameters (such as particle
masses) and coupling constants
(such as electric and other charges)
that go into physical calculations.
Some properties of subatomic
particles are not explained by the
standard model such as neutrino
masses and CP violation. Physicists
have been very active in
proposingextended and "improved"
models that go beyond the standard
model. Some of these
improvements go by the names of
super symmetry, technicolor, extra
dimensions, grand unification, and
string theory. Many of these
extensions involve weak long-range
forces that act in addition to the
standard gravitation of Newton and
Einstein. It is the effects of these
hypothetical new forces that we
addressed in our study.
Orbital motion, such as exhibited by
planets in the solar system, can be
used as a sensitive indicator for the
presence of non-gravitational weak
long-range forces. Newtonian
gravitation accounts for most
features of orbital motion, but any
additional non-gravitational forces
will cause perturbations to that
motion. The observation of small
orbital perturbations has a long
history and led to the discovery of
Neptune and Pluto. A small
precession of the orbit of Mercury,
unexplained by Newtonian physics,
was explained by Einsteinʼs theory of
gravitation in 1915. We proposed to
use precise observations of orbital
periods to place bounds on the size
of any additional weak long-range
forces. Examples of such forces that
have been considered include the
"antigravity" of dark energy, forces
associated with a presumed distance
dependence of the gravitational
"constant", forces induced from
higher-dimensional models of
gravitation, etc.
NEWS FROM PROF. PRATON
Prof. Praton kept busy in the last
year on a couple fronts.
Astrophotography enthusiasts will be
interested to hear that there has
been a breakthrough in the problem
of devising a way to align polar
mounts on the observing deck
despite not being able to see Polaris
from that location. Department
electronics engineer Steve
Spadafore has designed a fantastic
new undermount for the polar
mounts. His undermount has an
adjuster mechanism so smooth and
precise in operation that you, like
F&M provost-emeritus and amateur
astrophotographer extraordinaire
Bruce Pipes, may instantly want
one for your own.
(Praton, continued on pg. 6)
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Fall, 2008
(Praton, continued from pg. 5)
However, even more crucial than the
adjuster mechanism is the system
Steve devised for attaching the
mounts to the observing piers. His
system allows one to attach and
detach the mounts to the piers in
seconds rather than minutes, in
precisely the same position they
were when last used. This is huge,
since it means the mounts need only
be aligned once. This, together with
our newly calibrated flip-mirror
system for achieving instant good
focus, will greatly speed set up for
those desiring to give our cameras a
good work out. These
advancements have come largely
thanks to the labor and suggestions
of the volunteer "Improve
Astrophotography" squad, whose
members include Brian Burt ʼ10,
Alaina Stush ʻ10, Brian Devour
ʻ10, Arpita Roy ʻ09, and Jon Bock
ʼ12. Thanks yʼall (especially Brian B)
for all those nighttime hours!
Prof. Praton has also continued to
plug away at her research problems.
This summer she supervised two
Hackman students: rising junior
Brian Devour ʻ10 and rising senior
Boyko Perfanov ʻ09. Brian did a
study of possible redshift-space
artifacts in the Ursa Major region of
the Local Supercluster, continuing
work begun by past fummer Mike
Rothrock ʼ00. Boyko developed
improvements to the Candy model
simulated annealing algorithm for
finding filaments in galaxy
distributions, building on past work
by Arpita Roy ʼ09, Elisabeth
Bardenett ʼ07, and Micah
Dombrowski ʼ08.
Although Devour and Praton found
that not as much useful new data
has become available as one might
hope since the time of Rothrockʼs
project, they did build a nifty new
interactive application in
Mathematica for selecting galaxies
from 3D galaxy distribution maps.
Perfanov, meanwhile, advanced the
long-running Candy model project
substantially by rewriting the C++
code from scratch and adding new
features that make the algorithm
much more able to reliably
distinguish and trace both thick and
thin filaments, which is the long term
goal of this project.
ASTROPHYSICIST ANDREA
LOMMEN WINS NSF GRANT TO
PURSUE GRAVITATIONAL
WAVES
Prof. Andrea Lommen
Einstein predicted them. Princeton
scientists won the 1993 Nobel
Physics Prize for indirectly
demonstrating they exist. But no one
has directly detected gravitational
waves, or "ripples" in the space-time
continuum.
Andrea N. Lommen, assistant
professor of physics and astronomy
at Franklin and Marshall College,
(Lommen, continued on page 7)
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Fall, 2008
(Lommen, continued from page 6)
however, hopes to change that. And
she just won a highly competitive
grant of $654,917 to do so.
The National Science Foundation
recently selected Lommen as the
recipient of a CAREER award for her
project, "Gravitational Wave
Detection Using Pulsars."
The CAREER award is the NSF's
most prestigious grant supporting
early career development activities of
teacher-scholars who effectively
integrate research and education in
their projects. Only about 400
scientists receive the awards each
year, out of a pool of more than 2500
applicants.
This is Franklin & Marshall's second
CAREER award - Ryan Mehl,
assistant professor of chemistry,
wonone in 2005
"I'm very pleased that the NSF has
recognized the outstanding work that
Professor Lommen and her students
have done," says Richard A. Fluck,
associate dean of the faculty. "The
Foundation sees the promise of even
greater work from her in the future."
Lommen's project is both elegant
and ambitious. She proposes to use
observations of pulsars - "dead stars
with the mass of the sun and the size
of Lancaster that spin as fast as a
blender" - to detect gravitational
wave signatures.
"Think of pulsars as a lighthouse
beam," she says, putting her
complex topic in laymen's terms.
"Every time the star spins, a beam
cuts across the universe."
Those beams are like clocks, she
explains, "enormously regular in their
pulsations." Lommen's goal is to use
these convenient clocks, "donated by
the universe," to detect arrhythmias.
Instead of the regular bum-bum-bum
of a rotating pulsar, she's hoping to
find a bum-de-bum-bum. This
deviation in the rhythm could be the
signature of a gravitational wave.
Spinning dead stars called
pulsars cast beams of light across
warped space-time. An irregularity
in the beam could signal a
gravitational wave. (Image is
courtesy of Marjorie E. Gonzalez
at the University of British
Columbia.)
Albert Einstein's famous theory of
relativity predicted the existence of
gravitational waves, but so far,
observations have yet to capture
these phantoms. Any scientist who
successfully detects them will open
up new ways of looking at the
universe, aiding in the continual
quest to discover the origins of the
universe itself.
While Lommen's project focuses on
the heavens, it involves a great deal
of earthly collaboration - including
high school students, Franklin &
(Lommen, continued on page 8)
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Fall, 2008
(Lommen, continued from page 7)
Marshall undergraduates, a teaching
postdoctoral fellow and Lommen - in
all cases either mentoring or being
mentored on several different levels.
"All my life, I noticed I've gained a lot,
in both directions, from mentoring,"
she says. "I wouldn't be here if
people hadn't said 'you can do that.'
At the same time, being a mentor
has raised my own performance
level."
Numerous pulsar researchers will
participate, with the North American
Nano-Hertz Observatory of
Gravitational Waves (NANOGrav) in
the lead.
Franklin & Marshall undergraduates
will participate in the research,
introducing them to a global network
of astronomers.
A teaching postdoctoral fellow will
aid in the project, thus preparing him
or her for a lifetime of balanced
educational and research goals.
High school students, both in
Lancaster and Australia, will also
conduct observations in their
classrooms by remotely operating a
telescope that's part of Charles Sturt
University in Bathurst, Australia.
These halfway-around-the-world
observers will work in paired
classrooms, fostering young
scientists in an environment of
international collaboration. This Web
site-http://blackholenet.
mit.csu.edu.au/telescope/mai
n.asp -- will provide the window
through which high school students
will peer.
And finally, the project will involve
annual collaborative meetings with
the Center for Gravitational Wave
Physics at Penn State University as
well as joint efforts with international
gravitational wave and pulsar
researchers whose telescopes
regularly scour the void.
What happens if she is successful
and the research detects
gravitational waves? It could lead to
a breakthrough as momentous as
the invention of the telescope.
Detecting gravitational waves "won't
help us build better toilets or make
better sticky notes," she says wryly,
"but it will help us move beyond the
mere observation of light, or
electromagnetic radiation, which is
our only observational key to the
universe at the moment."
Fluck concurs. "This award will give
Professor Lommen and her students
- including Franklin & Marshall
College students and high school
students - the opportunity to study a
fundamental problem in physics and
astronomy," he says.
FAMILY UPDATES
Since our last issue we have had
another addition to the Physics and
Astronomy family. Joseph Lacey
was born October 22, 2007. Joey
joins big brother Charlie and proud
parents Scott and Sarah to round out
(Families, continued on page 9)
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Fall, 2008
(Families, continued from page 8)
the Lacey family.
The Lacey Family: Sarah, Joey,
Scott and Charlie
Update on those beautiful twin girls,
Mom Andrea Lommen writes: "On a
personal note, Rose and Xyla are
doing great. Theyʼll be 4 in
December. Xyla recently did an
experiment demonstrating the
conservation of momentum in
inelastic collisions. It involved falling
off a jungle gym and landing on her
front teeth. Her front teeth arenʼt
pretty, but sheʼs fine."
Rose Xyla
A STUDY OF CP VIOLATION IN
POSITRONIUM DECAY
Dominik Rastawicki and Professor
Adkins worked together during the
summer of 2008 to study how the
decay of positronium into photons
can be used as a probe of discrete
symmetries.
Discrete symmetries such as leftright
symmetry (parity, or P) and time
reversal symmetry (T) are important
symmetries in nature. Newtonian
dynamics is invariant under parity,
which means that for any possible
process the mirror image of that
process is also possible. Newtonian
dynamics also respects time reversal
symmetry since a movie of a
physical process played backwards
shows another possible process. A
third discrete symmetry known as
charge conjugation (C) also plays a
major role in particle physics.
Charge conjugation replaces each
particle by its corresponding
antiparticle. In a C symmetric theory,
for every particle process there is a
corresponding antiparticle process.
The best quantum description of
elementary particles, known as the
standard model, does not respect
these symmetries on a microscopic
scale, but the combined operation of
all three (known as CPT), is exact.
In the standard model P and C are
violated "maximally", but CP
violations (and so also T violations)
are small.
The small violation of CP symmetry
plays an important role in our picture
of the universe. At the present there
is an observed preponderance of
matter over antimatter by many
orders of magnitude, and this
asymmetry is supposed to be a
consequence of CP violating effects
early in the history of the universe.
Violation of CP symmetry has also
been seen in the lab. For example,
(Positronium, continued on page
10)
The Force
Fall, 2008
(Positronium, continued from
page 9)
the difference between the rate for a
certain decay process compared to
its CP "mirror image" process has a
small but measurable value. In the
standard model, CP violation can be
parameterized but not understood on
the basis of more basic principles.
The quest to understand CP violation
has led to a great deal of "beyond
the standard model" research.
Observation and study of CP
violation will be an important mission
for the new LHC (Large Hadron
Collider) now being commissioned at
CERN.
The electron-positron bound system
known as positronium has been
proposed as an alternative system
for the exploration of CP violation.
Positronium is easy to make in the
laboratory from positrons produced
by radioactive decay, its decay
products (photons) are easy to
detect, and its properties under the
CP symmetry are easy to analyze.
Except for the fact that CP violation
effects in positronium are known to
be small it would be the ideal system
for the study of CP. Evidence of CP
violation in positronium has been
searched for in the past, and recently
a new, more sensitive, experiment
has been proposed. In our Hackman
project we took a careful look at a
particular proposal for the detection
of CP violation and found that this
proposal is inadequate. In particular,
a certain three-photon correlation
among the momenta of final-state
photons is to be measured, and it
has been suggested that a non-zero
value for this correlation would be an
indication of CP violation. We have
shown that this particular correlation
must vanish under very general
principles (such as Lorentz
invariance), and so it not a good
probe for CP violation. We also
calculated a number of two-photon
correlations that should be
accessible to experiment.
SUMMER PULSAR PROJECTS
This summer, two Hackman students
worked on several pulsar projects
with Froney Crawford on campus.
Jen Moses '11 finished up a project
that Brian Devour '10 worked on
last summer to look for single
dispersed radio pulses in a pulsar
survey archive from the Parkes
telescope. This analysis was
originally motivated by the recent
discovery of a class of pulsars which
emit bright, transient radio bursts
(impulses) but which are not
detectable with the usual Fourier
techniques that are applied to detect
radio pulsars. This project became
more interesting after the
serendipitous discovery of a bright
millisecond radio burst originating
from a cosmological distance that
Froney and a team of colleagues
unexpectedly discovered in a
different survey archive (see above).
This latter source is a complete
mystery, but it is estimated that
hundreds of these cosmological
radio bursts occur in the sky every
(Summer, continued on pg 11)
The Force
Fall, 2008
(Summer, continued from pg 10)
day, and pulsar survey observations
are one of the few kinds of
observations that are sensitive to
these bursts on such short timescales.
Dean Altemose '09 began a
study of a very luminous radio pulsar
in the Large Magellanic Cloud which
exhibits unusual sputtering behavior
in its pulsed emission. This pulsar
appears to be related to the class of
pulsars known as "nullers", which
completely shut off their persistent
pulsed emission for minutes at a
time. It is not yet clear whether
Dean's pulsar is one of this class or
represents some kind of new class,
and how this all ties in to how
pulsars emit radiation in the first
place (which is still an open question
in many ways).
Jen also began to reduce the data
from the latest observing run at the
NURO telescope in Arizona. We
continued our long-term study of
three K-dwarfs in the Pleiades. She
did the photometric analysis of these
stars and laid out the documentation
for the procedure for future work.
She made light curves of these three
stars, and we will compare our
results with those from our
collaborators at Gettysburg.
PULSAR OBSERVING IN
AUSTRALIA
Brian Devour '10 accompanied
Froney to the Parkes telescope in
Australia for a week in January to
collect data for two pulsar projects.
One was the nulling pulsar study on
which Dean Altemose '09worked,
and the other was a very deep
search for radio pulsations from two
X-ray sources which are thought to
be neutron star systems. One of
these is a binary system which has
been observed to emit 6.8 second Xray
pulses during an X-ray outburst.
These search data were analyzed
using our Beowulf cluster in
Hackman.
CONFERENCE TRAVEL
Becky Sobel ʼ08
Prof. Larochelle and her research
student Rebecca Sobel ʼ08 travelled
to New Orleans to attend the Annual
March Meeting of the American
Physical Society. Over 7,000
physicists from around the world
were in attendance. Becky presented
a talk, "Sol-gel synthesis and
characterization of terbium doped tinoxide,"
which reported the results of
her year-long research project with
Prof. Larochelle. Prof. Larochelle
presented preliminary results from a
research project she is working on
with Prof. Krebs, "Trivalent
chromium probes in mixed
dicyanoargentate-dicyanoaurate
(Conference, continued on pg 12)
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Fall, 2008
(Conference, continued from pg
11)
single crystals." Prof. Larochelle also
attended a small conference in
Berkeley, CA in June to present
results from her newest project on a
possible scintillator material
("Scintillation properties of the novel
single crystal cerium
dicyanoargentate").
PUBLICATIONS
"Synthesis and spectral properties of
Ce[Ag(CN)2]3", C. L. Larochelle, J.
K. Krebs, Optical Materials, 2007.
"Tunable excited state energy
transfer in EuxLa1-
x[Ag.75Au.25(CN)2]3", C. L.
Larochelle, T. Seemuller, Journal
of Luminescence, 2008.
"Optical Memory and Multi-step
Luminescence Thermochromism in
Single Crystals of K2Na[Ag(CN)2]3",
M. A. Omary, J. C. F. Colis, C. L.
Larochelle, H. H. Patterson,
Inorganic Chemistry, 2007.
"Deep Searches for Radio Pulsations
and Bursts from Four Southern
Anomalous X-ray Pulsars" F.
Crawford, J. W. T. Hessels, & V. M.
Kaspi Astrophysical Journal, 662,
1183 (2007)
"Flux Densities and Radio
Polarization Characteristics of Two
Vela-like Pulsars" F. Crawford & C.
L. Tiffany Astronomical Journal, 134,
1231 (2007)
"A Bright Millisecond Radio Burst of
Extragalactic Origin" D. R. Lorimer,
M. Bailes, M. A. McLaughlin, D. J.
Narkevic, & F. Crawford Science,
318, 777 (2007)
"PSR J1856+0245: Arecibo
Discovery of a Young, Energetic
Pulsar Coincident with the TeV
Gamma-ray Source HESS
J1857+026" J. W. T. Hessels, D. J.
Nice, B. M. Gaensler, V. M. Kaspi,
D. R. Lorimer, D. J. Champion, A. G.
Lyne, M. Kramer, J. M. Cordes, P.
C. C. Freire, F. Camilo, S. M.
Ransom, J. S. Deneva, N. D. R.
Bhat, I. Cognard, F. Crawford, F. A.
Jenet, L. Kasian, P. Lazarus, J. van
Leeuwen, M. A. McLaughlin, I. H.
Stairs, B. W. Stappers, & A.
Venkataraman Astrophysical Journal
Letters, 682, L41 (2008)