Research Areas

The department of physics has concentrated its research activities within several fields of physics, with the result that a number of projects are available in each area. Undergraduate student research is arranged informally as early as the sophomore (or occasionally freshman) year at the initiation of the student or formally as a senior research project. Several undergraduates typically receive support for summer research under the auspices of the REU (Research Experiences for Undergraduates) program. Graduate students complete a small research project (Physics 491) during the summer following their second semester, and then undertake a larger, thesis project. Following is a description of current faculty research projects that may involve undergraduates, REU students, or graduate students.

Accelerator Physics
  • Experiment: Use of the Solenoidal Tracker (STAR) detector at the Relativistic Heavy Ion Collider (RHIC), A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC), and other accelerator experiments to understand quark gluon plasmas. (Reed)

Astronomy and Astrophysics

  • Theory: Ultraviolet spectroscopy and gas dynamics of interacting binary systems; orbits of binary stars; N-body dynamics. (DeLeoMcClusky)
  • Observation: Observational studies to understand the formation and evolution of stars. Particular areas of interest are young open clusters, binary stars, X-ray binaries and pulsars, the formation of disks in Be stars, and the origin of magnetic fields in massive stars. (McSwain)  Discovery of transiting extra-solar planets (exoplanets) and variable stars. Lehigh is a member of the KELT exoplanet survey. Other research on exoplanets, eclipsing binary stars, and stellar astrophysics, with the NASA Kepler mission, the APOGEE survey, LSST, and the NASA TESS mission. (Pepper)
Atomic, Molecular, & Optical Physics
  • Theory: Charge exchange collisions; fine-structure changing collisions; optical processes in gases; molecular hyperfine spectroscopy. (Hickman)
  • Experiment: Collisional processes in atomic vapors including excitation transfer and “energy pooling” line-broadening, quenching, diffusion, resonance exchange and velocity-changing collisions; molecular spectroscopy of bound singlet and triplet states of alkali diatomics, photodissociation, predissociation, and bound-free emission. (HuennekensKim)
Biophysics
  • Theory: Physical and engineering principles involved in the assembly of actin proteins into filaments and larger scale structures. Statistical mechanics and soft matter physics applied to actin protein assemblies and the emergent collective properties  Equilibrium and nonequilibrium properties of protein phase transitions. (Vavylonis, Gunton)
  • Experiment: Application of optical imaging, trapping, and manipulation for cell mechanics studies (Ou-Yang). Use of nanomaterials for optical imaging of cells; carbon nanotube nanotoxicity. (Rotkin)
Computational physics
  • Several areas involve the use of state-of-the-art computers to address large-scale computational problems. Areas of interest include atom-atom collisions, simulations of tokamak plasmas, the statistical behavior of ensembles of many particles, the calculation of electronic wave functions for molecules and solids, and the multi-scale modeling of nano-bio systems. (GuntonKritzHickmanRotkin)
Condensed Matter Physics
  • Theory: Electronic and vibrational properties of defects in semiconductors and insulators (FowlerRickman). Optical and electronic properties of two-dimensional layered materials (TDLM); models for growth of single- and multi-layered graphene (Rotkin).
  • Experiment: Charge transport in insulators and semiconductors; nonlinear optical spectroscopy (Biaggio). Point defects in insulating materials with ferroelectric domain walls and other dopants; optical spectroscopy under application of hydrostatic pressure, and magnetic fields; carrier localization in wide band gap semiconductors (Dierolf). Quantum transport behavior of electrons, conduction in ultrasmall silicon MOSFETs and gallium-arsenide devices and carbon nanotubes at low temperature and high magnetic field (Licini). Defects in semiconductors. Current interest is in defect complexes that contain light-element impurities such as H, C, O, and N. Vibrational spectroscopy and uniaxial stress techniques are used to elucidate microscopic properties (Stavola). Raman and neutron scattering, dielectric and ultrasonic spectroscopies, collective vibrational dynamics of disordered ferroelectrics and glasses (Toulouse). Near-field and Fourier optical characterization of layered materials; near-field interfacial heat conductance (Rotkin).
Cosmology and String Theory
  • Theory: Quantum field theory and string theory, and their applications to theoretical cosmology, quantum gravity, particle theory, and strongly coupled gauge theories. (Cremonini)
High Energy Physics
  • Theory: Fundamental aspects and phenomenological applications of string theory, gravitational descriptions of quantum field theory, gauge/string dualities. (Cremonini)
  • Experiment: Examination of the quark gluon plasma (QGP) created in heavy ion collisions by using particle jets and heavy flavor quarks as probes of the medium. (Reed)
Nano Science and Technology
  • Theory: Quantum mechanics of low-dimensional systems; many-body effects in nanocarbon materials; modeling of interaction between nano and biological systems; solvation and aggregation; optics of molecular systems; quantum and near-field optics; interfacial heat conductance; NEMS. (Rotkin)
  • Experiment: Near-field optics; near-field heat conductance; surface characterization; mass and energy transport in soft matter, DNA/nanotube hybrids, rare-earth complexes; microfluidics. (Rotkin)
Nonlinear Optics and Photonics
  • Experiment: Multiple orders of light-matter interactions. Time-resolved spectroscopy of second and third-order nonlinear optical effects in organic and inorganic materials. Optical frequency conversion and all-optical switching (Biaggio). Fiber optics. Nonlinear effects in optical fibers and waveguides (DierolfToulouse). Plasmonics and near-field photonics (Rotkin).
Plasma and Fusion
  • Theory: Integrated modeling codes are developed and used to predict temperature, momentum and density profiles in magnetically confined controlled fusion plasma experiments. Theoretically derived physics models are developed for use in these codes and detailed comparisons are made between our simulations and experimental data in order to understand the physics of transport and confinement in plasmas. There are active collaborations with theory and experimental groups, both nationally and internationally. (Kritz)
  • Experiment: Collisional and collisionless phenomena of very dense plasmas in or near a local thermodynamic equilibrium; anomalies in radiation transport properties; lowering of ionization potentials in dense plasmas; laser-produced plasmas. (Kim)
Soft Condensed Matter Physics and Complex Fliuds
  • Experiment: Nonlinear dynamics in fluid systems; dynamics of small particle suspensions; light scattering. Polymer and colloid physics (KimOu-Yang). Physics of atto-fluidics transport in micellar/gelated materials; aggregation in bio-mimetic materials (Rotkin).

Statistical & Thermal Physics
  • Theory: Pattern formation in nonlinear, non-equilibrium systems. Kinetics of first order phase transitions focusing on crystallization of globular proteins. Cell-cell communication via calcium oscillations (KimGunton). Solvation models; water nanoscale complexes (Rotkin).
  • Experiment: Intrinsic fluctuations in fluids under external forcing, such as Brownian motion; chaotic transitions; light scattering from fractals; 1/f-dynamics of granular avalanches (Kim). Near-field Kapitza conductance (Rotkin).