Physics Faculty Research
Dr. Armendariz-Picon studies the origin and evolution of the universe. He is particularly interested in the nature of dark energy and dark matter, and in the origin of the initial inhomogeneities that later became the galaxies and clusters that fill our universe.
- C. Armendariz-Picon, “On the Expected Production of Gravitational Waves During Preheating,” JCAP, 2019 (2019) 012 https://arxiv.org/abs/1905.05724.
- C. Armendariz-Picon, “When Does the Inflaton Decay?,” JCAP, 1805 (2018) 018 https://arxiv.org/abs/1708.09755.
- C. Armendariz-Picon and G. Şengör, “BRST Quantization of Cosmological Perturbations,” JCAP, 1611 (2016) 016 https://arxiv.org/abs/1606.03823.
- C. Armendariz-Picon and J. T. Neelakanta , “How Cold is Cold Dark Matter?” JCAP, 1403 (2014) 049 https://arxiv.org/abs/1309.6971.
Dr. Jahncke's research interests are in optics and optical properties of materials. She uses techniques such as Raman spectroscopy, ellipsometery, and near-field scanning optical microscopy to characterize materials. Her current research is in collaboration with Dr. Hill in the Chemistry Department using Raman spectroscopy to characterize the heterobimetallic materials made by the Hill research group.
- Jahncke, C. L. Isabel Bogacz, and Adam Hill. “Using a Fabry Perot interferometer to narrow a laser line spectrum for Raman Spectroscopy applications,” in preparation.
- Jahncke, C L, O Brandt, KE Fellows, and H. D. Hallen. “Choosing a preamplifier for tuning fork signal detection in scanning force microscopy," Review of Scientific Instruments 75 (2004): 2759-2761.
- Hallen, HD and CL Jahncke, “The electric field at the apex of a near-field probe: implications for nano-Raman spectroscopy” Journal of Raman Spectroscopy 34 (2003): 655-662.
- Jahncke, C.L. and H.D. Hallen. “Stabilizing wide bandwidth, tuning fork detected force feedback with nonlinear interactions.” Journal of Applied Physics 93 (2003): 1274-1282.
- Hallen H.D., E.J. Ayars, and C.L. Jahncke. “The effects of probe boundary conditions and propagation on nano-Raman spectroscopy.” Journal of Microscopy 210 (2003): 252-254.
- Jahncke, C.L., S.H. Huerth, Beverly Clark III, and H.D. Hallen. “Dynamics of the tip-sample interaction in near-field scanning optical microscopy and the implications for shear force as an accurate distance measure.” Applied Physics Letters 81 (2002): 4055-4057.
Dr. Johnson studies the history of modern physics, particularly nuclear and chemical physics. Her work has focused on the close analysis of the evolution of scientific ideas, such as the wave theory of light and the nuclear shell model. She also studies the history of women in science and the role of collaboration in scientific creativity.
- Karen E. Johnson, “From natural history to the nuclear shell model: chemical thinking in the work of Mayer, Haxel, Jensen, and Suess,” Physics in Perspective, 6 (2004) 295-309.
- Karen E. Johnson, “Spontaneous human collaboration: using disciplinary thinking to study interdisciplinary work,” St. Lawrence University 2003 Piskor Faculty Lecture.
Dr. Koon's specialty is materials science. Specifically, he probes materials by looking at how they treat their electrons. He measures charge transport, particularly the Hall effect, which is the result of electrical current curving under the influence of a magnetic field. With his students at SLU he has both calculated and measured how local defects alter measured electrical quantities -- a question of interest for quality control in microelectronics fabrication -- and has used resistivity, Hall effect, and optical transmission to monitor hydrogen absorption in metals -- of interest for the storage of hydrogen fuel for transportation. He has carried out these studies with SLU students in his own laboratory at St. Lawrence, in laboratories in Costa Rica, Spain, and the Czech Republic, and with colleagues from Denmark. He is known internationally and across disciplines for having proven that polar bear hair does NOT behave as an ultraviolet lightpipe and that the iridescence of butterflies acts as a sunblock, not a solar collector. Teaching science fiction in the First Year Program led him into translating science fiction from Cuban and other authors from Spanish to English, which he has published online and in print. Koon is a two-time Fulbright scholar.
- D.W. Koon, M. Heřmanová, J. Náhlík. Electrical Conductance Sensitivity Functions for Convex and Cloverleaf van der Pauw geometries. Measurement Science and Technology, Volume 26, Number 11 (2015). https://iopscience.iop.org/article/10.1088/0957-0233/26/11/115004
- D.W. Koon, F. Wang, D.H. Petersen, O. Hansen. Sensitivity of resistive and Hall measurements to local inhomogeneities: Finite-field, intensity, and area corrections. Journal of Applied Physics. Vol. 116, No. 13, p. 133706. (2014) https://orbit.dtu.dk/en/publications/sensitivity-of-resistive-and-hall-measurements-to-local-inhomogen
- J.R. Ares, F. Leardini, P. Díaz-Chao, J. Bodega, D.W. Koon, I.J. Ferrer, J.F. Fernández, C. Sánchez. Hydrogen desorption in nanocrystalline MgH2 thin films at room temperature. Journal of Alloys and Compounds. 495 (2), 650–654. (2010)
- D.W. Koon, J.R. Ares, F. Leardini, J.F. Fernández, I.J. Ferrer. Polynomial-interpolation algorithm for van der Pauw Hall measurements in a metal hydride film. Meas. Sci. Technol. 19, 105106. (2008)
Dr. O'Donoghue's research is primarily in radio astronomy and she has conducted observations with the Very Large Array and Arecibo radio telescopes. She has also observed dwarf galaxies in the visible band at the Vatican Advanced Technology Telescope and the optical spectra of stars using the 90” Bok telescope at Kitt Peak and the 1.5 m telescope at Cerro Tololo, Chile. She is currently a member of the ALFALFA undergraduate team conducing a blind spectral survey of the sky visible from the Arecibo Observatory cataloging clouds of neutral hydrogen.
- Durbala, A., Finn, R. A., Odekon, M. C., Haynes, M. P., Koopmann, R. A., O’Donoghue, A. A.,The ALFALFA-SDSS Galaxy Catalog, Astronomical Journal, 2020, 160, 271-286 https://iopscience.iop.org/article/10.3847/1538-3881/abc018
- A.A. O’Donoghue, M.P. Haynes, R. Koopmann, M. Jones, R. Giovanelli, T.J. Balonek, D.W. Craig, G.L. Hallenbeck, G.L. Hoffman, D.A. Kornreich, L. Leisman, and J.R. Miller. The Arecibo Pisces-Perseus Supercluster Survey: I. Harvesting ALFALFA, Astronomical Journal, 157, No. 2 (2019) https://iopscience.iop.org/article/10.3847/1538-3881/aaf890/pdf
- M.P. Haynes, R. Giovanelli, B.R. Kent, E.A.K. Adams, T.J. Balonek, D.W. Craig, D. Fertig, R. Finn, C. Giovanardi, G. Hallenbeck, et al. The Arecibo Legacy Fast ALFA Survey: The ALFALFA Extragalactic H i Source Catalog. Astrophysical Journal, 861, No. 1. (2018) http://iopscience.iop.org/article/10.3847/1538-4357/aac956/meta
- P. Troischt, R. Koopman, A. O'Donoghue, M.C. Odekon, M.P. Haynes.The Undergraduate ALFALFA Team: A Collaborative Model for Undergraduate Research in Major Long-term Astronomy Projects. Council on Undergraduate Research Quarterly, 36, Issue 4 (Summer 2016) https://www.cur.org/what/publications/journals/curq/issues/#summer2016
- M.P. Haynes, R. Giovanelli, A.M. Martin, K.M. Hess, A. Saintonge, E.A.K. Adams, G. Hallenbeck, G.L. Hoffman, S. Huang, B.R. Kent, et al. The Arecibo Legacy Fast ALFA Survey: The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function. Astronomical Journal. 142, No. 5. (2011) http://iopscience.iop.org/1538-3881/142/5/170/article
- R.O. Gray, C.J. Corbally, R.F. Garrison, M.T. McFadden, E.J. Bubar, C.E. McGahee, A.A. O'Donoghue, E.R. Knox. Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc— The Southern Sample. Astronomical Journal. 132, No. 1. (2006) http://iopscience.iop.org/1538-3881/132/1/161
Dr. Pirbhai's research is at the interface of physics and biology. It focuses on developing single- walled carbon nanotube (SWCNT) based nanosensors that can control the specialization of neural stem cells turning to neural cells namely neurons and astrocytes; a process known as differentiation. The electrical conductivity, strong mechanical properties, and similar morphological characteristics of SWCNTs to neurons make it promising as therapies for Alzheimer's and Parkinson's diseases. The implementation of nanosensors has, however, been hindered because we do not understand how SWCNTs interact with cells. One of the goals of my research is to characterize and create a model for this interaction.
Dr. Pirbhai's research is related to polarized light. He investigates why materials affect the polarization of light. Lately, he has been looking into using polarized light for medical diagnosis. His other interest includes electron beam physics, and he is currently building a system to study single crystal and polycrystalline diffraction patterns.
Miller is involved in the ALFALFA Project, a consortium of 20 universities led by Cornell University and funded by the NSF, that uses the 1000-ft. antenna of the National Astronomy and Ionosphere Center's Arecibo Observatory to measure extragalactic abundance of neutral Hydrogen (HI). As part of this group, he has observed at Kitt Peak, Arecibo and Green Bank, and has brought students to an annual workshop at the Arecibo and Green Bank observatories.
- A.A. O’Donoghue, M.P. Haynes, R. Koopmann, M. Jones, R. Giovanelli, T.J. Balonek, D.W. Craig, G.L. Hallenbeck, G.L. Hoffman, D.A. Kornreich, L. Leisman, and J.R. Miller. The Arecibo Pisces-Perseus Supercluster Survey: I. Harvesting ALFALFA, Astronomical Journal, Vol. 157, No. 2 (2019) https://iopscience.iop.org/article/10.3847/1538-3881/aaf890/pdf
- M.P. Haynes, R. Giovanelli, B.R. Kent, E.A.K. Adams, T.J. Balonek, D.W. Craig, D. Fertig, R. Finn, C. Giovanardi, G. Hallenbeck, et al. The Arecibo Legacy Fast ALFA Survey: The ALFALFA Extragalactic H i Source Catalog. Astrophysical Journal. Vol. 861, No. 1. (2018) http://iopscience.iop.org/article/10.3847/1538-4357/aac956/meta
- M.P. Haynes, R. Giovanelli, A.M. Martin, K.M. Hess, A. Saintonge, E.A.K. Adams, G. Hallenbeck, G.L. Hoffman, S. Huang, B.R. Kent, et al. The Arecibo Legacy Fast ALFA Survey: The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function. Astronomical Journal. Vol. 142, No. 5. (2011) http://iopscience.iop.org/1538-3881/142/5/170/article