Faculty Research Profiles

Jean Bellissard

My research concerns mathematical problems raised by various questions of condensed matter physics. I am interested in the electronic and transport properties of aperiodic solids and I have used non-commutative geometry to study conceptual problems in the theory of the quantum Hall effect. Recently I have turned my interest toward random matrix theory to address problems such as the Anderson localization-delocalization transition and the low temperature conductivity and phonon spectrum of quasicrystals.

Michael Chapman

My laboratory investigates fundamental topics in contemporary quantum mechanics by manipulating the quantum behavior of single atoms and photons. This research employs lasers to confine and cool atoms to micro-Kelvin temperatures inside a vacuum chamber. Recent successes include all-optical formation and trapping of Bose-Einstein condensates and the Nevatron-a storage ring for ultracold atoms. Our research employs state-of-the-art laser and optical technologies, as well as high-speed electronics and vacuum technology.
Chapman Research Labs

Mei-Yin Chou

The objective of my theoretical research is to investigate the electronic structure of condensed matter. For many systems, calculations are performed from first principles quantum mechanics with no adjustable parameters. This has been made possible by advances in computational methods developed in the past decades. The purposes of these studies are to provide unambiguous explanations for various interesting phenomena observed experimentally in clusters, solids, and surfaces, and to make reliable predictions of new material properties from microscopic quantum theories.

Edward Conrad

My area of specialization is the experimental study of solid surfaces using high-resolution low-energy electron diffraction (HRLEED) and synchrotron-based x-ray diffraction. I am particularly interested in phase transitions on surfaces and the dynamical behavior of surface defect structures such as steps and islands. A recent success is the determination of atomic diffusion processes on silicon using a sophisticated analysis of time-correlation scattering data. Our research employs ultrahigh vacuum techniques and high-speed electronics.

Jennifer Curtis

My laboratory focuses on the physics of the cell that directly influences biological function. We investigate several biological topics: pericellular matrix-modulatd cell adhesion, phagocytosis, and active transport. In all three areas, we probe the coupling of the mechanical and chemical circuitry of the cell.
The unifying theme of these biologically disparate subjects is the underlying role played by soft condensed matter and statistical mechanics in these systems. Our interdisciplinary lab focuses on integrating the diverse biological, technical and conceptual knowledge required to approach these problems from a biophysicist's viewpoint
The Curtis Group - Cell Physics Laboratory

Predrag Cvitanovic

Recent developments have greatly increased our insights in turbulence, the unsolved problem of classical physics. I want to crack it. A theory might be within reach, but it requires every tool in a theorist's toolbox, from numerically intensive solutions of PDEs to quantum field theory to mathematics of zeta functions. The very interdisciplinary nature of this research is especially rewarding: the theory has many totally ununticipated applications, with ideas and experimental inspiration coming from many disciplines: atomic physics, biology, meteorology, engineering, to name but a few.

Dragomir Davidovic

The focus of our research is on electronic and spin-polarized transport in nanometer scale structures, which include metallic nanoparticles and flakes of graphite and graphene. In nanometer scale particle, the electronic states are quantized and discrete levels lead to novel behaviors. In one experiments we are injecting spin in individual Aluminum nanoparticles, creating a spin accumulation inside Aluminum. There is a finite overlap between injected spins and the nanoparticle eigenstates, making the spin-relaxation time much longer than in bulk aluminum. Similarly, in small graphitic flakes, a two dimensional electron gas forms, and our studies involve magnetoresistance and spin accumulation measurements at low temperatures.

Alberto Fernandez De Las Nieves

Soft materials are materials whose properties are determined by internal structures with dimensions between atomic sizes and macroscopic scales. They are characterized by energies that are typically comparable to KT. As a result, they have low elastic moduli, often ~1-10 Pascals. Typical soft materials include liquid crystals, polymers, colloidal suspensions and emulsion drops. These materials, unlike conventional simple liquids, are locally heterogeneous and can have broken symmetries that affect their physical properties. Hence, although they often exhibit liquid-like behavior, soft materials also often exhibit properties of solids.

Our laboratory studies the physics of soft materials with a focus on the connection between microscopic order and macroscopic properties. The underlying theme is to pursue basic understanding and address fundamental questions. However, we also address applied problems and pursue industrial collaborations since many of the materials we study can be viewed as model systems for those that are often used in applications. Current projects include (i) studying the phase behavior and properties of packed soft objects, (ii) understanding the consequences of confinement and curvature over the equilibrium states of ordered materials, which in many cases require the existence of topological defects in their ground states, and (iii) developing microfluidic techniques to study fundamental fluid mechanic questions and to generate new materials through directed assembly and mixing of the components.

Walter De Heer

My experimental research program covers two directions: graphene and metal clusters. Graphene has been envisioned as a promising material for next generation electronics. My interest in graphene is focused on growth of large scale epitaxial graphene of high quality and the study of its remarkable electronic properties. The ultimate goal of this research is to build novel electronic devices on epitaxial graphene and realize all-graphene electronics. Clusters are small nanometer diameter particles containing less than 1000 atoms. The goal of this research program is to explore how the properties of materials evolve as a bulk material is constructed one atom at a time. In our experiment clusters are produced by laser vaporization at cryogenic temperatures. Our experimental methods include electric and magnetic deflection, visible and UV laser spectroscopy, and time-of-flight mass spectroscopy. Recently our work has focused on clusters of ferromagnetic materials such as iron and cobalt, as well as an anomalous ferroelectric state discovered in niobium clusters.
Graphene Lab

Ahmet Erbil

My research focuses on the creation and understanding of advanced material systems that might lead to the discovery of novel physical phenomena or to applications in electronics, optics, or sensors. The program components include: (1) the growth and processing of materials; (2) the study of bulk, thin film, interface and surface properties; and (3) theoretical modeling. Among the materials of interest are ferroelectrics, silicon, II-VI semiconductor compounds, transition metal oxides, high-temperature superconductors, and diamonds.

Phillip First

A primary goal of my experimental research is to develop an understanding of condensed matter systems at atomic length scales. The main experimental tools are scanning tunneling microscopy (STM) and ballistic electron emission microscopy (BEEM). These methods rely on the quantum-mechanical tunnel effect to obtain atomically resolved maps of the electronic structure of surfaces, clusters, and buried layers. Current research in my lab addresses the fundamental physics of nanocrystals (nanometer-scale atomic clusters), graphitic nanostructures, and spin-dependent transport.
STM Lab

Daniel Goldman

Our research addresses problems in nonequilibrium systems that involve interaction of physical and biological matter with complex materials (like granular media) that typically flow when stressed. For example, how do organisms like lizards, crabs, and cockroaches generate appropriate musculoskeletal dynamics to scurry rapidly over substrates like sand, bark, leaves, and grass. The study of novel biological and physical interactions with complex media can also lead to the discovery of principles that govern the physics of the media. Our approach is to integrate laboratory and field studies of organism biomechanics with systematic laboratory studies of physics of the substrates, as well as to create mathematical and physical (robot) models of both organism and substrate.
CRAB Lab

James Gole

My laboratory has been concerned with (1) the action of nanostructures as they are introduced to nonporous/microporous interfaces and their subsequent ability to enhance interaction and thus to promote an increased sensitivity and a more efficient conversion and transduction, (2) the development of new, high yield, nanoscale, exclusive processes forming the novel interactive nanostructures necessary for this effective interface modification, and (3) the development of "Active" micro/nano surfaces. In developing these interfaces, we seek to identify the micro-nanoscale materials phenomenon that form the framework for new interface transformations which can be used for marking, tagging, and sensing.

Roman Grigoriev

Spatially extended nonequilibrium systems such as fluids and biological excitable media are described by potentially very many coupled degrees of freedom and display dynamics that can range from ordered (pattern formation near onset) to very disordered (fully-developed turbulence). While the methods of nonlinear science have achieved a certain "universal" (in the spirit of equilibrium critical phenomena) understanding of low-dimensional behavior in spatially extended systems, current tools for describing these systems fail when the dynamics are high-dimensional, involving many spatial and temporal degrees of freedom. This inability to handle spatiotemporal complexity presents a fundamental barrier to the application of the methods of nonlinear science in many disciplines.

 Professor Grigoriev's research is focused in the following areas:

* Theory of spatiotemporal chaos
* Spatially extended dynamics in living systems
* Pattern formation in technological processes
* Control of spatially extended systems

The main goal of this research is to apply existing tools of nonlinear science to important problems arising from advances in technology and biology such as microfluidics or the dynamics and control of heart fibrillation. More information about current research activities can be found on the group webpage.

Brian Kennedy

My research focuses on theoretical topics in quantum optics and atomic physics, including applications to quantum information processing using atoms and photons. Recent work has involved analysis of methods of entanglement of atomic spin wave excitations with photons, and its use to create entanglement of remote atomic excitations in cold atomic vapors. Other recent investigations include the influence of quantum noise on spatio-temporal instabilities in nonlinear optics and the transport dynamics of ultra-cold Fermi gases in an optical lattice.

Markus Kindermann

The subject of my research is the physics of nanostructures - very small, but not quite microscopic, man-made devices. Due to advances in the field of nanotechnology, a large variety of such structures recently has become available. Borderline between the world of macroscopic, classical physics and that of the microscopic quantum world, they exhibit an array of interesting, and previously unexplored, phenomena. Typically these phenomena are electrical in nature, but also the mechanical properties of nano-devices can be non-classical. The goal of my research is to contribute to a theoretical understanding of nanostructures. Often the insights gained from such research can be used to predict new interesting effects or to optimize nano-devices for applications such as quantum computing. The challenge as well as the fascination of the theory of systems on the nanoscale derives from an interplay between quantum coherent effects and many-particle interactions.

Alexander Kuzmich

My laboratory is devoted to the development of new techniques for quantum measurements, particularly feedback and control of the internal and external degrees of freedom of cold, trapped atoms. Such techniques can be applied to quantum information processing, e.g., to create one-photon light sources and many-particle atomic entanglement. I am also interested in the application of new quantum interrogation techniques to the measurement of fundamental constants.
Quantum Optics

Uzi Landman

As the Director of the Georgia Tech Center for Computational Materials Science, I am responsible for a wide-ranging theoretical program that develops and exploits classical and quantum molecular dynamics to study dynamical processes at the nanoscale. Problems of current interest include non-equilibrium growth processes, phase transformations, surface reaction dynamics, catalysis, atomic-scale friction and lubrication, confined complex fluids, electron localization and excitation dynamics of small clusters, and the dynamics of cluster fission.

Alexei Marchenkov

My research program focuses on the physics of reduced-dimensional heat flow and thermal equilibration in nanostructures. In my ultra-low temperature laboratory, DC SQUID-based noise thermometry provides the temperature sensitivity and time resolution necessary to detect individual phonons. I am interested in both the fundamental aspects of these phenomena and in the development of practical applications, such as ultra-sensitive bolometry and micro-refrigeration.

Toan Nguyen

Our research is in the field of theoretical biophysics. At the moment, we study the assembly process of immunodeficiency virus (or HIV) - the causative agent of the well-known AIDS disease. This study is even more important due to recent interest in biological community toward assembly-oriented viral therapy. Using continuum elastic theory of shells and membranes, we study the physical problems related to HIV capsid self-assembly and how it enters/leaves the cell. We study how this process can be influenced by various parameters such as the tension and bending stiffness of the cell membrane and the viral envelope membrane, the strength of interaction between HIV capsid proteins, ionic strength of cell cytoplasm. Our recent success includes an explanation for the famous conical shape of HIV capsid after in-vivo maturation, understanding partial budding of HIV particles from cell and how RNA viral genome are packaged inside its capsid.

Michael Pustilnik

I am interested in the theory of mesoscopic systems. Mesoscopic physics deals with diverse objects whose size spans the range between tens of nanometers to a few microns. The properties of these objects are very different from that of both microscopic (molecule-size) and macroscopic ones. Topics of recent interest include electronic transport in quantum dots and quantum wires, and the localization of waves in random media.

Chandra Raman

My laboratory explores ultra-low temperature quantum degenerate gases. We use laser cooling and magnetic trapping to bring atoms to temperatures in the nano-Kelvin regime. With these techniques we can study Bose-Einstein condensation (BEC), a phenomenon where a macroscopic number of atoms share the same wavefunction. It leads to new collective effects and allows unprecedented control over atomic wave functions. Currently my group is focused on dual BECs and the prospect of producing ultracold polar molecules.
Chandra Raman Group

Elisa Riedo

My experimental research activity is at the crossroads of physics, chemistry, biology, and microengineering and it is centered on the study of forces at the nanoscale. These forces can have different origin: friction forces, capillary forces, viscous forces, electrostatic forces, ligand-receptor forces and many others. Specific issues under investigation include capillary condensation at the nanoscale and in the origin of nano-friction between dry and lubricated surfaces. Stick and slip phenomena, confinement of liquids between surfaces, mechanical properties of nanocontacts and interaction forces between biomolecules are investigated by means of different techniques based on the atomic force microscopy (AFM).
picoForce Laboratory

Carlos Sa de Melo

My theoretical research program focuses on superconductors, ferromagnets, semiconductors and biological systems. Current activities include: the properties of superconductors in high magnetic fields; the crossover from BCS to Bose-Einstein superconductivity, magnetic coupling in ferromagnetic/superconductor multilayers, macroscopic quantum phenomena in ferroelectrics and ferromagnets, Bose-Einstein ccondensation of excitons, quantum computing with p-SQUIDs, colossal magnetoresistive materials, and quantum mutations in DNA.

Michael Schatz

The origin of pattern formation is the central theme of my laboratory. Presently, we are focused on low-gravity fluid physics, an emerging field known as microfluidics. Experiments in fluids are ideal for our purposes because the governing equations and control parameters are known. This work provides terrestrial scientific support for future space experiments. In the future, we plan investigations of pattern formation in material science and biology; potential areas of study include instabilities and defects in thin organic films and the role of spatio-temporal chaos in cell differentiation.
Patter Formation & Control Laboratory

Rick Trebino

My group develops optical techniques and devices, especially those using ultrashort laser pulses. We developed Frequency-Resolved Optical Gating (FROG), the first (and best!) technique for accurately measuring the complete electric field versus time of an arbitrary laser pulse. More recent developments include techniques for measuring the complete spatio-temporal electric field of these pulses, and we have been able to do so even for focused pulses. We have also measured the most complex ultrashort laser pulses ever generated, with time-bandwidth products in excess of 1000. In addition, we have developed an astrobiological polarimeter to look for chirality (and possible life) in extraterrestrial environments.
Georgia Center for Ultrafast Optics

Turgay Uzer

I use quantum, classical, and semi-classical methods to study nonlinear dynamics in microscopic (atomic/molecular) systems whose classical behavior can exhibit chaos. Many of these systems form atomic-scale laboratories on which ideas concerning the quantum mechanics of chaotic systems can be tested. Current research areas include: energy levels, spectroscopy and ionization of highly excited atoms in external fields, periodic orbits and their influence on spectra, nondispersive electronic wavepackets in atoms, dynamics of energy flow in molecules, and mechanisms of unimolecular chemical reactions.

Kurt Wiesenfeld

Nonlinear dynamics, especially complex systems with many degrees of freedom, is the focus of my theoretical research. Areas of current interest are : (a) stochastic resonance, including its relevance in biological systems; (b) spontaneous synchronization in populations of coupled oscillators (especially superconducting circuits); (c) dynamical beam-steering in very high frequency antenna arrays; and (d) avalanching behavior and self-organized criticality (renormalization group approach; magnetic avalanches and flux-creep).

Li You

The research conducted in my group spans a wide range of topics in theoretical light/matter interactions. At present, I am focusing on optical pulse propagation through Bose-Einstein condensates, non-resonant light scattering from Bose and Fermi gases, the statistical properties of atom lasers, atomic collisions mediated by long range dipole-dipole interactions, evaporative cooling of trapped fermions, and quantum entanglement as it applies to quantum logic and quantum computing.
Physics of Ligth/Matter interactions

Andrew Zangwill

My research program is devoted to the theory of nanoscale magnetic systems. This includes spintronics?Xan emerging field that seeks to exploit the electron spin degree of freedom as a control parameter in electronic devices. At the present time, my students and I are using analytic calculations and computer simulations to study magnetic switching and the electromagnetic response of magnetic heterostructures. A topic of special interest is the possibility of spin wave amplification by stimulated emission of radiation (SWASER).