Biological Physics

Biological physicists use principles of physics to understand biological processes. The spatial scale of these processes spans the single molecule to the biological network. On the single molecule level, physicists make significant contributions in the development of experimental methods that illuminate molecular conformations, measure interactions with other molecules and monitor the formation of scaffolding that forms the cellular supporting environment. On the network level, collective behaviors and systems far from equilibrium prevail, requiring tools from non-linear dynamics and statistical mechanics to quantify these interactions. Fabrication of integrated micro-devices applied to human health also falls under the purview of the biological physicist. These sophisticated tools utilizing state-of-the art technologies improve quality of life and health care as they speed drug delivery and facilitate the diagnosis of disease.

At Georgetown, biological physicists use advanced optical imaging techniques such as high-speed confocal microscopy and optical tweezers to study a variety of systems including properties of cell motility, neurite migration in 3D bio-matrices and biopolymer rheology. Arrays of extracellular microelectrodes are used to study pattern formation in in vitro neural networks. The Georgetown Nanoscience and Microtechnology Lab (GNuLab) is home to a wide range of state-of-the-art fabrication and characterization instruments to develop bio-technologies for the healthcare industry.

Daniel Blair — soft glasses, colloidal and polymer physics, crumpling, biopolymer rheology, confocal microscopy of soft materials, granular dynamics and statics

John Currie — materials science of thin solid films, industrial and applied physics, surface and interface chemical physics, semiconductor electrical and electro-optical devices and technology, renewable energy generation and storage, polymer physics, electrochemistry, environment monitoring technologies

Rhonda Dzakpasu — spatio-temporal pattern formation in in vitro neural systems, extracellular multi-electrode array recordings, computational modeling of coherent activity in neural networks, development of non-linear methods of data analysis

David Egolf — statistical physics of nonequilibrium dynamical systems, including fluids, granular media, cardiac and neural tissue, and biopolymer networks; effective theories of QCD.

Ryan McAllister — cellular biophysics, cancer cell motility and invasion, live-cell imaging, fluid dynamics, nonlinear dynamics

Makarand Paranjape — micro-/nano-technologies for sensors, actuators, and structural systems, silicon/polymer and carbon nanotube device fabrication, biomedical engineering

Jeff Urbach — cellular biophysics, physics of soft matter, biomaterials, biomedical optics, granular dynamics, fluid dynamics, nonlinear dynamics

Hard Condensed Matter

Condensed matter and materials physics seeks to understand the diverse and often unexpected phenomena that emerge when large numbers of constituents, such as electrons, atoms, or molecules, are brought together to form macroscopic matter. "Hard" condensed matter generally deals with materials with structural rigidity, such as crystalline solids, glasses, metals, insulators, and semiconductors. The term hard matter is commonly used to refer to matter governed by atomic/molecular forces and quantum mechanics.

Experimental and computational/theoretical research groups at Georgetown are interested in superconductivity, magnetism, and other novel states of hard matter that arise from correlations between constituent particles; structural, electronic, and transport properties of materials at both the macro and nano scales; and processes in which light interacts with and scatters off of solids.

Paola Barbara — superconductivity, superconducting devices, transport properties of nanowires and nanoscale electronic devices

Jim Freericks — strongly correlated electrons (charge and thermal transport and nonequilibrium effects), transport in multilayered nanostructures, resonant inelastic X-ray scattering, ultracold atoms in optical lattices (especially mixtures, dipolar molecules, and the Hubbard model) undergraduate understanding of quantum mechanics, student satisfaction with the major.

Amy Liu — structural, electronic, and vibrational properties of materials, including novel superconductors, thermoelectrics, charge-density-wave solids, clusters, and materials under pressure; simulation of calcium dynamics in cells

Marcos Rigol — strongly correlated quantum many-body systems, quantum phase transitions and quantum criticality, nonequilibrium dynamics of quantum systems, superconductivity, ultracold gases in optical lattices, magnetism, disorder, computational physics

Micro and Nano Technologies

Micro and nano technologies include a wide range of advanced techniques used to fabricate and study artificial systems with dimensions ranging from several micrometers (one micrometer is one millionth of a meter) to a few nanometers (one nanometer is one billionth of a meter). Fabrication techniques fall into two classes. "Top-down" approach is used to cut macroscopic materials down to small size by using lithography techniques. "Bottom-up" approach uses growth or self-assembly of nanometer structures that are then connected to larger structures. These technologies create many research opportunities: What are the properties of wires which are only a few atoms wide? Do transistors still work when their size approaches the atomic scale? What new (and possibly useful) properties result when we can manipulate individual atoms?

Micro and nanotechnology research at GU includes novel nanoparticles for medical imaging, carbon nanotube sensors, MEMS for health monitoring or drug delivery and nanomaterials for organic photovoltaic devices. State-of-the-art fabrication and characterization tools are available in the Physics Department within the Georgetown Nanoscience and Microtechnology Laboratory (GNuLab).

Paola Barbara — superconductivity, superconducting devices, transport properties of nanowires and nanoscale electronic devices

John Currie — materials science of thin solid films, industrial and applied physics, surface and interface chemical physics, semiconductor electrical and electro-optical devices and technology, renewable energy generation and storage, polymer physics, electrochemistry, environment monitoring technologies

Makarand Paranjape — micro-/nano-technologies for sensors, actuators, and structural systems, silicon/polymer and carbon nanotube device fabrication, biomedical engineering

Edward Van Keuren — optics, nanoparticle synthesis and characterization, application of nanoparticles for organic photovoltaic devices and biomedical imaging and therapy

Optics and Imaging

Optics is the study of light – how electromagnetic radiation in a certain range of frequencies propagates and interacts with matter, and how it can be used for applications such as telecommunications, imaging and materials characterization. Research in optics spans a wide range, from highly theoretical topics such as quantum optics and optical vortices to very applied areas such as fiber optics and laser technology.

At Georgetown, optics research in the physics department reflects this wide range, with active research in the creation of new algorithms for theoretical calculation of beam propagation in waveguides, development of novel imaging methods to study soft matter and biological systems and the use of high powered lasers to create novel nanomaterials. Imaging is a particular strength, with high speed confocal, fluorescence and Raman microscopes used for materials characterization. Faculty collaborate on optics projects with colleagues at a number of major universities (University of Maryland, Tohoku University) national labs (NIST, NRL) and companies (Luna Innovations, Areté Associates).

Daniel Blair — soft glasses, colloidal and polymer physics, crumpling, biopolymer rheology, confocal microscopy of soft materials, granular dynamics and statics

Ryan McAllister — cellular biophysics, cancer cell motility and invasion, live-cell imaging, fluid dynamics, nonlinear dynamics

Jeff Urbach — cellular biophysics, physics of soft matter, biomaterials, biomedical optics, granular dynamics, fluid dynamics, nonlinear dynamics

Edward Van Keuren — optics, nanoparticle synthesis and characterization, application of nanoparticles for organic photovoltaic devices and biomedical imaging and therapy

Physics Education

Physics Education Research is the systematic investigation of the teaching and learning of physics. Its goals include the improvement of student understanding of physics, improvement of teacher preparation in physics, improvement of student attitudes toward physics, and improvement of scientific reasoning skills and appreciation for the sciences among non-science majors, among others. Physics Education Researchers at Georgetown University are involved in developing, implementing, and assessing research-based curricula. Other projects involve the incorporation of technology into large lecture classes, and the development and assessment of physics courses for non-science majors.

Mark Esrick — teaching of graduate physics courses, particularly quantum mechanics

Jim Freericks — strongly correlated electrons (charge and thermal transport and nonequilibrium effects), transport in multilayered nanostructures, resonant inelastic X-ray scattering, ultracold atoms in optical lattices (especially mixtures, dipolar molecules, and the Hubbard model) undergraduate understanding of quantum mechanics, student satisfaction with the major.

Earl Skelton — teaching with technology: assessment of the learning effects of modern teaching tools such as clickers, computer based assignments, and podcasted lectures.

Soft Condensed Matter

Soft-matter physics, is a young sub-field of condensed matter physics. This field is generally described as materials oriented with a strong focus on understanding macromolecular assemblies. These meso-scale or medium sized constituents often self-assemble or organize into macro-scale materials and demonstrate many novel and unexpected phenomenon. Many of these materials are extremely familiar from everyday life and have a vast number of technologically important applications. For example we utilize personal care and food products that are comprised of materials such as liquid crystals, gels, foams, polymers, granular matter and emulsions just to name a few. Many current theoretical descriptions of soft matter are derived through classical physics, and are often described using the tools of equilibrium and non-equilibrium statistical mechanics, symmetry breaking and many body physics.

At Georgetown, we are interested in developing tools and methods to better describe these complex systems. Experimentally, we use a variety of tools including high level processing of confocal microscopy data, optical tweezing and bulk- and micro- rheological methods. We utilize these techniques to study the behavior of systems such as soft glasses, colloidal dispersions, biopolymers, elastic membranes and cells. A large component of our work is focused on relating the microstructural properties of spatially heterogeneous systems to their bulk mechanical properties.

Daniel Blair — soft glasses, colloidal and polymer physics, crumpling, biopolymer rheology, confocal microscopy of soft materials, granular dynamics and statics

Ryan McAllister — cellular biophysics, cancer cell motility and invasion, live-cell imaging, fluid dynamics, nonlinear dynamics

Jeff Urbach — cellular biophysics, physics of soft matter, biomaterials, biomedical optics, granular dynamics, fluid dynamics, nonlinear dynamics

David Egolf — statistical physics of nonequilibrium dynamical systems, including fluids, granular media, cardiac and neural tissue, and biopolymer networks; effective theories of QCD.

Statistical Physics

Statistical physics is a field of physics that studies the behaviors of large collections of interacting objects. Traditionally, these objects have been atoms, molecules, magnetic spins, or volumes of fluid, but in recent decades, statistical physicists have been studying many other types of interacting groups of "objects", such as species in ecosystems, traders in financial markets, chemicals in cardiac and neural tissue, electrical activity within neural circuits, and grains in sand piles. Using various mathematical techniques, statistical physicists attempt to describe, understand, and predict the macroscopic behaviors of the collections (such as the phase of matter, transport or structural properties, spatial or temporal patterns, etc.) without a detailed knowledge of the behavior of each individual object. For collections in equilibrium or near equilibrium, much of the behavior is well-understood; however, for collections of particles far from equilibrium (for example, when input and output of energy is not balanced at every moment of time), the underlying rules governing the behaviors are still being discovered.

At Georgetown, we are studying a variety of classical and quantum systems using experiments, computation, and theory. Most of our work involves trying to understand situations that are either far from equilibrium or subjected to imposed disorder. The objects of our studies are wide ranging and include atoms, magnetic spins, biopolymers, biological cells, granular material, colloids, fluids, and electrical activity within neural circuits.

Rhonda Dzakpasu — spatio-temporal pattern formation in in vitro neural systems, extracellular multi-electrode array recordings, computational modeling of coherent activity in neural networks, development of non-linear methods of data analysis

David Egolf — statistical physics of nonequilibrium dynamical systems, including fluids, granular media, cardiac and neural tissue, and biopolymer networks; effective theories of QCD.

Jim Freericks — strongly correlated electrons (charge and thermal transport and nonequilibrium effects), transport in multilayered nanostructures, resonant inelastic X-ray scattering, ultracold atoms in optical lattices (especially mixtures, dipolar molecules, and the Hubbard model), undergraduate understanding of quantum mechanics, student satisfaction with the major.

Marcos Rigol — strongly correlated quantum many-body systems, quantum phase transitions and quantum criticality, nonequilibrium dynamics of quantum systems, superconductivity, ultracold gases in optical lattices, magnetism, disorder, computational physics

Ultracold Gases

Ultracold gases are a relatively young field in atomic and molecular physics. They became world wide known after the achievement of Bose-Einstein condensation in 1995 (see Nobel Prize in Physics in 2001). In more recent years, these systems have attracted a great deal of attention in other areas in physics, such as condensed matter physics, nuclear physics, and quantum information. This is because of the high degree of control and tunability that can be achieved experimentally. Remarkably, experimentalists can make use of Feshbach resonances to tune the interaction strength between atoms and decide whether it should be attractive or repulsive. The addition of optical potentials, like optical lattices, also allow then to play with the interaction strength and the effective dimensionality of the system. As a matter of fact, ultracold gases allow physicists to create experimental realizations of model Hamiltonians that are used in condensed matter physics to understand the properties of real materials.

At Georgetown, we are mainly interested in understanding the equilibrium and nonequilibrium properties of ultracold gases when they are loaded in optical lattices. The study of the nonequilibrium dynamics of nearly isolated quantum systems is another of the unique possibilities opened by experiments on this field. In equilibrium, we study bosons, fermions, and their mixtures, which enable the realization of many exotic quantum phases of matter. We also investigate pattern formation in mixtures of different mass atoms, with possible applications to cooling within a lattice.

Jim Freericks — strongly correlated electrons (charge and thermal transport and nonequilibrium effects), transport in multilayered nanostructures, resonant inelastic X-ray scattering, ultracold atoms in optical lattices (especially mixtures, dipolar molecules, and the Hubbard model) undergraduate understanding of quantum mechanics, student satisfaction with the major.

Marcos Rigol — strongly correlated quantum many-body systems, quantum phase transitions and quantum criticality, nonequilibrium dynamics of quantum systems, superconductivity, ultracold gases in optical lattices, magnetism, disorder, computational physics