From the Cover…

.. epigraph:: “Helliwell achieves a rare clarity. For instance, the derivation of the standard kinematic results starting from Einstein's postulates is outstandingly clear. Throughout he shows an unusual and sympathetic appreciation of the problems that are faced by the beginning student.” -- John Taylor, University of Colorado .. epigraph:: “*Special Relativity* is definitely much better than the books I have read on this topic, and I would recommend it to any instructor who plans to teach a course on this topic. For anyone teaching special relativity as a part of a Modern Physics course, this book offers valuable supplementary reading.” -- Shirvel Stanislaus, Valparaiso University


A new class of observables is introduced which aims to characterize the superstructure of an event, that is, features, such as color flow, which are not determined by the jet four-momenta alone. Traditionally, an event is described as having jets which are independent objects; each jet has some energy, size, and possible substructure such as subjets or heavy flavor content. This description discards information connecting the jets to each other, which can be used to determine if the jets came from decay of a color- singlet object, or if they were initiated by quarks or gluons. An example superstructure variable, pull, is presented as a simple handle on color flow. It can be used on an event-by-event basis as a tool for distinguishing previously irreducible backgrounds at the Tevatron and the LHC.


We demonstrate the operation of a device that can produce chitosan nanoparticles in a tunable size range from 50–300 nm with small size dispersion. A piezoelectric oscillator operated at megahertz frequencies is used to aerosolize a solution containing dissolved chitosan. The solvent is then evaporated from the aerosolized droplets in a heat pipe, leaving monodisperse nanoparticles to be collected. The nanoparticle size is controlled both by the concentration of the dissolved polymer and by the size of the aerosol droplets that are created. Our device can be used with any polymer or polymer/therapeutic combination that can be prepared in a homogeneous solution and vaporized.


Absorption enhancement in thin metal-backed solar cells caused by dipole scatterers embedded in the absorbing layer is studied using a semi-analytical approach. The method accounts for changes in the radiation rate produced by layers above and below the dipole, and treats incoherently the subsequent scattering of light in guided modes from other dipoles. We find large absorption enhancements for strongly coupled dipoles, exceeding the ergodic limit in some configurations involving lossless dipoles. An antireflection-coated 100-nm layer of a-Si:H on Ag absorbs up to 87% of incident above-gap light. Thin layers of both strong and weak absorbers show similar strongly enhanced absorption.

Recent Publications

Student authorFaculty author


Thomas Helliwell

Special Relativity

University Science Books, Sausalito, 2010.
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Jason Gallicchio and Matthew D. Schwartz

Seeing in Color: Jet Superstructure

Physical Review Letters 105 (2010) 022001.
PDF document
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Andrew P. Higginbotham, Thomas D. Donnelly, Shenda M. Baker, and Ian K. Wright

Generation of Nanoparticles of Controlled Size Using Ultrasonic Piezoelectric Oscillators in Solution

ACS Applied Materials and Interfaces 2 (2010) 2360-2364.
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J. Parker, David W. Mar, Joshua R. Puzey, John H. Hankinson, Kevin P. Byram, C. Lee, Michael K. Mayeda, Richard C. Haskell, Qimin Yang, S. Greenfield, and R. Epstein

Thermal links for the implementation of an optical refrigerator

Journal of Applied Physics 105 (2009) 013116.

Andrew P. Higginbotham, Octavi E. Semonin, Sandra A. Bruce, Clarence W. Chan, David A. Mann, M. Maurer, W. Bang, I. V. Churina, J. Osterholz, I. Kim, T. Ditmire, and Thomas D. Donnelly

Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments

Review of Scientific Instruments 80 (2009) 063503.
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Peter N. Saeta, Harry A. Atwater, Vivian E. Ferry, Jeremy N. Munday, and Domenico Pacifici

How much can guided modes enhance absorption in thin solar cells?

Optics Express 17 (2009) 20975-20990.
PDF document

Gregory Minton and Vatche Sahakian

New mechanism for nonlocality from string theory: UV-IR quantum entanglement and its imprints on the CMB

Physical Review D 77 (2008) 026008.

Junbo Park, K. W. Alt, Caitlin M. Furjanic, Dariya K. Draganova, Samuel D. Eisenberg, D. Tighe, M. J. Carey, J. A. Borchers, Patricia D. Sparks, and James C. Eckert

Thickness of the Pinned Layer as a Controlling Factor in Domain Wall Formation During Training in IrMn-based Spin Valves

Journal of Applied Physics 103 (2008) 07C111.

S. Kneip, B. I. Cho, D. R. Symes, H. A. Sumeruk, G. Dyer, I. V. Churina, A. V. Belolipetski, A. Henig, O. Werhan, E. Förster, Thomas D. Donnelly, and T. Ditmire

K-shell Spectroscopy of Plasmas Created by Intense Laser Irradiation of Micron-scale Cone and Sphere Targets

High Energy Density Physics 4 (2008) 41-48.

Junbo Park, S. M. Watson, Caitlin M. Furjanic, Dariya K. Draganova, M. J. Carey, J. A. Borchers, Chih-Yung Chen, Patricia D. Sparks, and James C. Eckert

Probing the Effect of Structural Roughness on Domain Wall Formation in Spin Valves Using the Off-Specular Reflectivity Technique

IEEE Transactions on Magnetism 44 (2008) 2839-2841.