James M Valles
James M Valles
Royce Family Professor of Teaching Excellence in Physics and Professor of Physics
Overview
Professor Valles joined the faculty at Brown in 1992. Prior to this he was an Assistant Professor of Physics at the University of Oregon from 1989 to 1992 and a postdoctoral member of the technical staff at AT&T Bell Laboratories from 1987 to 1989. He received his Ph.D. from the University of Massachusetts in 1988 and his Bachelor of Arts from Dartmouth College in 1981. He is the recipient of an Alfred P. Sloan Foundation Fellowship and a Fellow of the American Physical Society. He was awarded the Harriett Sheridan for Distinguished Contribution to Teaching and Learning and the Philip J. Bray Award for Excellence in Science Teaching. As a Provost Faculty Teaching Fellow, he co-facilitates the Seminar for Transformation Around Anti-Racist Teaching that is offered through the Sheridan Center for Teaching and Learning.
Brown Affiliations
Research Areas
Cell biology | electron tunneling | magnetic levitation | magnetic manipulation of cells | microorganism swimming | nanoscale films | SIT | Superconductivity
Publications
| Zhang, Xue, Joy, James C, Zhao, Chenwei, Kim, Jin Ho, Fernandes, Gustavo, Xu, J M, Valles, James M. "Evaporating metal nanocrystal arrays." Nanotechnology, vol. 28, no. 10, 2017, pp. 105302. |
| Nguyen, H. Q., Hollen, S. M., Shainline, J., Xu, J. M., Valles, J. M. "Driving a Superconductor to Insulator Transition with Random Gauge Fields." Scientific Reports, vol. 6, 2016, pp. 38166. |
| Nguyen, H. Q., Hollen, S. M., Valles, J. M., Shainline, J., Xu, J. M. "Disorder influences the quantum critical transport at a superconductor-to-insulator transition." Physical Review B, vol. 92, no. 14, 2015. |
| Jung, Ilyong, Powers, Thomas R., Valles, James M. "Evidence for Two Extremes of Ciliary Motor Response in a Single Swimming Microorganism." Biophysical Journal, vol. 106, no. 1, 2014, pp. 106-113. |
| Hollen, S. M., Fernandes, G. E., Xu, J. M., Valles, J. M. "Fate of the Bose insulator in the limit of strong localization and low Cooper-pair density in ultrathin films." Physical Review B, vol. 90, no. 14, 2014. |
| Jung, Ilyong, Guevorkian, Karine, Valles, James M. "Trapping of Swimming Microorganisms at Lower Surfaces by Increasing Buoyancy." Phys. Rev. Lett., vol. 113, no. 21, 2014. |
| Hollen, S. M., Fernandes, G. E., Xu, J. M., Valles, J. M. "Collapse of the Cooper pair phase coherence length at a superconductor-to-insulator transition." Physical Review B, vol. 87, no. 5, 2013. |
| Hollen, S.M., Shainline, J., Xu, J.M., Valles, J.M. "Cooper pair insulator phase induced in amorphous Pb0.9Bi0.1 thin films." Physica C: Superconductivity, vol. 486, 2013, pp. 23-25. |
| Hollen, S M, Valles, J M. "Cooper pair islanding model of insulating nanohoneycomb films." J. Phys.: Conf. Ser., vol. 376, 2012, pp. 012002. |
| Hollen, S. M., Nguyen, H. Q., Rudisaile, E., Stewart, M. D., Shainline, J., Xu, J. M., Valles, J. M. "Cooper-pair insulator phase in superconducting amorphous Bi films induced by nanometer-scale thickness variations." Physical Review B, vol. 84, no. 6, 2011. |
| Stewart, M.D., Nguyen, H.Q., Hollen, S.M., Yin, Aijun, Xu, J.M., Valles, J.M. "Enhanced suppression of superconductivity in amorphous films with nano-scale patterning." Physica C: Superconductivity, vol. 469, no. 13, 2009, pp. 774-777. |
| Nguyen, H. Q., Hollen, S. M., Stewart, M. D., Shainline, J., Yin, Aijun, Xu, J. M., Valles, J. M. "Observation of Giant Positive Magnetoresistance in a Cooper Pair Insulator." Phys. Rev. Lett., vol. 103, no. 15, 2009. |
| Guo, Yongxing, Liu, Yifeng, Oldenbourg, Rudolf, Tang, Jay X., Valles, James M. "Effects of osmotic force and torque on microtubule bundling and pattern formation." Physical Review E, vol. 78, no. 4, 2008. |
| Stewart, M. D., Yin, Aijun, Xu, J. M., Valles, J. M. "Magnetic-field-tuned superconductor-to-insulator transitions in amorphous Bi films with nanoscale hexagonal arrays of holes." Physical Review B, vol. 77, no. 14, 2008. |
| Coleman, Chasity B., Allen, Patricia L., Valles, James M., Hammond, Timothy G. "Transcriptional regulation of changes in growth, cell cycle, and gene expression ofSaccharomyces cerevisiae due to changes in buoyancy." Biotechnology and Bioengineering, vol. 100, no. 2, 2008, pp. 334-343. |
| Coleman, Chasity B., Gonzalez-Villalobos, Romer A., Allen, Patricia L., Johanson, Kelly, Guevorkian, Karine, Valles, James M., Hammond, Timothy G. "Diamagnetic levitation changes growth, cell cycle, and gene expression ofSaccharomyces cerevisiae." Biotechnology and Bioengineering, vol. 98, no. 4, 2007, pp. 854-863. |
| Guo, Yongxing, Liu, Yifeng, Tang, Jay X., Valles, James M. "Polymerization Force Driven Buckling of Microtubule Bundles Determines the Wavelength of Patterns Formed in Tubulin Solutions." Phys. Rev. Lett., vol. 98, no. 19, 2007. |
| Stewart, M. D., Yin, A., Xu, J. M., Valles, J. M. "Superconducting Pair Correlations in an Amorphous Insulating Nanohoneycomb Film." Science, vol. 318, no. 5854, 2007, pp. 1273-1275. |
| Guevorkian, Karine, Valles, James M. "Aligning Paramecium caudatum with Static Magnetic Fields." Biophysical Journal, vol. 90, no. 8, 2006, pp. 3004-3011. |
| Stewart, M. D., Long, Zhenyi, Valles, James M., Yin, Aijun, Xu, J. M. "Magnetic-flux periodic response of nanoperforated ultrathin superconducting films." Physical Review B, vol. 73, no. 9, 2006. |
| Liu, Y., Guo, Y., Valles, J. M., Tang, J. X. "Microtubule bundling and nested buckling drive stripe formation in polymerizing tubulin solutions." Proceedings of the National Academy of Sciences, vol. 103, no. 28, 2006, pp. 10654-10659. |
| Barber, R. P., Hsu, Shih-Ying, Valles, J. M., Dynes, R. C., Glover, R. E. "Negative magnetoresistance, negative electroresistance, and metallic behavior on the insulating side of the two-dimensional superconductor-insulator transition in granular Pb films." Physical Review B, vol. 73, no. 13, 2006. |
| Long, Zhenyi, Stewart, M. D., Valles, James M. "Super-weakly coupled superconductivity in ultrathin superconductor–normal-metal bilayers." Physical Review B, vol. 73, no. 14, 2006. |
| Guevorkian, K., Valles, J. M. "Swimming Paramecium in magnetically simulated enhanced, reduced, and inverted gravity environments." Proceedings of the National Academy of Sciences, vol. 103, no. 35, 2006, pp. 13051-13056. |
| Long, Zhenyi, Valles, James M. "Early Stage Morphology of Quench Condensed Ag, Pb and Pb/Ag Hybrid Films." Journal of Low Temperature Physics, vol. 139, no. 3-4, 2005, pp. 429-438. |
| Guevorkian, Karine, Valles, James M. "In situ imaging of micro-organisms in intense magnetic fields." Review of Scientific Instruments, vol. 76, no. 10, 2005, pp. 103706. |
| Valles, J.M., Maris, H.J., Seidel, G.M., Tang, J., Yao, W. "Magnetic levitation-based Martian and Lunar gravity simulator." Advances in Space Research, vol. 36, no. 1, 2005, pp. 114-118. |
| VALLES, J.M., GUEVORKIAN, K. "MANIPULATING CELLS WITH STATIC MAGNETIC FIELDS." Materials Processing in Magnetic Fields, 2005. |
| Pavenayotin, Niravun, Stewart, M. D., Valles, James M., Yin, Aijun, Xu, J. M. "Spontaneous formation of ordered nanocrystal arrays in films evaporated onto nanopore array substrates." Appl. Phys. Lett., vol. 87, no. 19, 2005, pp. 193111. |
| Long, Zhenyi, Stewart, M. D., Kouh, Taejoon, Valles, James M. "Subgap Density of States in Superconductor-Normal Metal Bilayers in the Cooper Limit." Phys. Rev. Lett., vol. 93, no. 25, 2004. |
| Guevorkian, Karine, Valles, James M. "Varying the effective buoyancy of cells using magnetic force." Appl. Phys. Lett., vol. 84, no. 24, 2004, pp. 4863. |
Research
Research Overview
Professor Valles does research in experimental condensed matter physics, in the areas of: superconductivity; electron correlation effects in disordered metals and nanostructures; and in using magnetic fields as a tool for cell biology and biopolymerization.
Research Statement
Valles' group performs research in two distinct areas: low temperature condensed matter physics and biological physics.
The condensed matter physics research focuses on uncovering and exploring the properties of the possible phases, such as superconducting, insulating, or magnetic, that metals assume at very low temperatures. Which phase emerges in a given system can be determined by a subtle interplay of its geometry, its microscopic structure and whether or not it is in a magnetic field. Most recently, Valles has focused on films of metals that are so thin that they exhibit two dimensional properties. Some of these come with their own nanostructure, while others are patterned with features on the scale of nanometers. The specific topics that this research addresses are the two dimensional superconductor to insulator and superconductor to metal transitions, localization phenomena, proximity effects in mesoscopic systems, and the physics of thin film growth on low temperature and nanostructured substrates.
Biological physics work in the Valles lab has been directed at developing the use of intense, static magnetic fields as a means of manipulating biological systems. They have shown that cell division in frog eggs, the swimming of microorganisms, and biopolymerization phenomena can be modified and investigated with static magnetic fields.
The condensed matter physics research focuses on uncovering and exploring the properties of the possible phases, such as superconducting, insulating, or magnetic, that metals assume at very low temperatures. Which phase emerges in a given system can be determined by a subtle interplay of its geometry, its microscopic structure and whether or not it is in a magnetic field. Most recently, Valles has focused on films of metals that are so thin that they exhibit two dimensional properties. Some of these come with their own nanostructure, while others are patterned with features on the scale of nanometers. The specific topics that this research addresses are the two dimensional superconductor to insulator and superconductor to metal transitions, localization phenomena, proximity effects in mesoscopic systems, and the physics of thin film growth on low temperature and nanostructured substrates.
Biological physics work in the Valles lab has been directed at developing the use of intense, static magnetic fields as a means of manipulating biological systems. They have shown that cell division in frog eggs, the swimming of microorganisms, and biopolymerization phenomena can be modified and investigated with static magnetic fields.
Funded Research
1990-92 Alfred P. Sloan Foundation Fellowship
1991-94 National Science Foundation, "Electron Tunneling Studies of Ultrathin Normal Metal Films"
1991-94 Office of Naval Research, "Electron Tunneling Studies of Ultrathin Films Near the Metal Insulator Transition"
1995-98 Office of Naval Research, "Ballistic Electron-Emission Microscopy Studies of High Tc Superconductor Normal Metal Interfaces"
1995-98 National Science Foundation, "Ultra Low Temperature Transport and Scanning Tunneling Microscopy Studies of Quench Condensed Films"
1997-98 - Salomon Faculty Research Award with Professor K. Mowry -
1998-00 National Science Foundation, "Tunneling and Transport Studies of Ultrathin Films of Metals and Superconductors"
1999-00 National Science Foundation, "Manipulation of Cell Division with Static Magnetic Fields"
2002-04 National Science Foundation, "Quantum Phase Transitions in Nanostructured Superconductors in 2D"
2001-05- NASA, "Magnetic Field Gradient Levitation System for Physics and Biophysics"
2004-2007 NASA, "Microscopic Studies of Gravi-Sensitive Microtubule Assembly in Simulated Variable Gravity Conditions", co-PI with Professor Jay Tang
2005 Jet Propulsion Laboratory "Investigations of the Adaptation of Euglena to Changes in a Simulated Gravity Environment"
2006-2009 National Science Foundation, "Vortices and Quasiparticles in Superconducting Films in Small Order Parameter Amplitude Limit"
1991-94 National Science Foundation, "Electron Tunneling Studies of Ultrathin Normal Metal Films"
1991-94 Office of Naval Research, "Electron Tunneling Studies of Ultrathin Films Near the Metal Insulator Transition"
1995-98 Office of Naval Research, "Ballistic Electron-Emission Microscopy Studies of High Tc Superconductor Normal Metal Interfaces"
1995-98 National Science Foundation, "Ultra Low Temperature Transport and Scanning Tunneling Microscopy Studies of Quench Condensed Films"
1997-98 - Salomon Faculty Research Award with Professor K. Mowry -
1998-00 National Science Foundation, "Tunneling and Transport Studies of Ultrathin Films of Metals and Superconductors"
1999-00 National Science Foundation, "Manipulation of Cell Division with Static Magnetic Fields"
2002-04 National Science Foundation, "Quantum Phase Transitions in Nanostructured Superconductors in 2D"
2001-05- NASA, "Magnetic Field Gradient Levitation System for Physics and Biophysics"
2004-2007 NASA, "Microscopic Studies of Gravi-Sensitive Microtubule Assembly in Simulated Variable Gravity Conditions", co-PI with Professor Jay Tang
2005 Jet Propulsion Laboratory "Investigations of the Adaptation of Euglena to Changes in a Simulated Gravity Environment"
2006-2009 National Science Foundation, "Vortices and Quasiparticles in Superconducting Films in Small Order Parameter Amplitude Limit"
Background
Education and Training
| Year | Degree | Institution |
|---|---|---|
| 1988 | PhD | University of Massachusetts |
| 1981 | BA | Dartmouth College |
Honors and Awards
1981 Magna Cum Laude, Dartmouth College
1982-84 Graduate Fellow, University of Massachusetts
1986-87 IBM Graduate Fellow
1990-92 Alfred P. Sloan Fellow
1993 Elected to Sigma Xi
2012 Harriet W. Sheridan Award for Distinguished Contribution to Teaching and Learning
2013 Elected Fellow of the American Physical Society
2019 Philip J. Bray Award for Excellence in Science Teaching
2019 Excellent Research Award from The Magneto-Science Society of Japan
Affiliations
Affiliations
American Physical Society Member
Teaching
Teaching
| PHYS 0040 - Basic Physics B |
| PHYS 0070 - Analytical Mechanics |
| PHYS 0470 - Electricity and Magnetism |
| PHYS 1530 - Thermodynamics and Statistical Mechanics |