# Research

## Condensed Matter Physics

Condensed matter physics deals with fundamental questions concerning the behavior of systems comprised of large numbers of strongly interacting degrees of freedom. On the one hand, it seeks to understand the collective, system-wide, physical properties that arise from what are usually well understood basic microscopic interactions. On the other hand, it seeks to understand the behavior of microscopic degrees of freedom, such as charge and spin, when embedded in condensed matter environments.

Having its beginnings in*solid state physics*, primarily concerned with the electronic properties of solids, modern condensed matter physics has grown to include study of such diverse systems as solids, liquids, superfluids, glasses, polymers, gels, colloids, neural networks, macromolecules, and indeed any system in which many interacting basic components lead to complex or qualitatively new behavior. Research in modern condensed matter physics spans the range from understanding the properties of exotic and artificially fabricated materials, to investigating and controlling quantum coherence in nano- to macro- scale objects, to fundamental questions concerning ordering, phase transitions, and critical behavior in classical and quantum statistical systems.

### Department Research

Our faculty and laboratories conduct a variety of research in both experimental and theoretical condensed matter physics:

### Experiment

Ranga Dias - Professor Dias' research focuses on materials at extreme pressure and temperature conditions, where materials alter their properties in many fundamental ways that are not present at ambient conditions. His main interests are high temperature superconductivity, magnetism, and superfluidity in the vicinity of quantum phase transitions.

Yongli Gao - Professor Gao's research is in experimental surface physics using photoemission spectroscopy, inverse photoemission spectroscopy, scanning probe microscopy, and time-resolved 2-photon photoelectron spectroscopy. He has been working on the surface electronic structure, electronic interactions, morphology of interfaces and interface formation, and ultrafast electron dynamics in metals, organic and inorganic semiconductors, and solar cell materials.

Chunlei Guo - Professor Guo's interest is in laser-matter interactions. He has pioneered the use of laser processing to produce a wide range of highly functionalized materials, including black and colored metals as well as superhydrophilic and superhydrophobic surfaces. He is also interested in applying these surfaces for various technological applications.

John Nichol - Professor John Nichol's research focuses on studying and manipulating single electrons in solid-state systems. Particular areas of interest are quantum computing with spin qubits, many-body quantum coherence, and coherent spin-phonon coupling.

Lewis Rothberg - Professor Rothberg studies the science of light emission, charge photogeneration and charge transport that underpins future applications of organic materials in lighting, flexible displays, electronic paper and organic solar cells. The techniques we use span the range from transient spectroscopy of excited state relaxation to charge modulation spectroscopy in devices.

Roman Sobolewski - Professor Sobolewski's current interests are concentrated on the physics of ultrafast phenomena in condensed matter systems using time-resolved femtosecond spectroscopy. He studies novel nanostructured electonic and optoelectronic semiconducting and superconducting materials and devices for single-photon quantum detection and the generation and detection of THz radiation transients.

Nick Vamivakas - Professor Vamivakas's research efforts center on light-matter interactions at the nanosclae, using optics to interrogate and contral both artifical and naturally occuring solid state quantum emitters. Potential applications range from optical metrology to quantum information science.

Stephen Wu - Professor Wu's research involves using new quantum materials to create novel electronic devices beyond Moore's law computation. Topics such as spintronics, topological electronics, and multifunctional complex oxide based transistors are explored from the perspective of materials synthesis, nano-fabrication, and low-noise device characterization.

### Theory

Hanan Dery – Professor Dery’s research is in the theory of *spintronics*, which deals with the control and flow of electronic spin in condensed matter systems. In particular he studies the optical and transport properties of two-dimensional materials with emphasis on transition-metal dichalcogenides, focusing on how excitons and other few-body complexes are affected by Coulomb interactions with the Fermi sea around them, with impurities and with phonons.

Ignacio Franco – Professor Franco works at the interface of chemistry, physics, optics and nanoscience, using theory and simulation to develop new methods to probe and control the behavior of matter by means of external stimuli. Topics of interest include quantum dynamics, investigating basic de-coherence processes in the condensed phase, exploring frontiers of the laser-matter interaction, and advancing single-molecule spectroscopies that can be constructed in the context of nanoscale junctions.

Gourab Ghoshal – Professor Ghoshal is a statistical physicist who works in the field of complex systems. His research interests are in the theory and applications of complex networks as well as non-equilibrium statistical physics, game theory, econophysics, dynamical systems and the origins of life.

Andrew Jordan – Professor Jordan’s research focuses on theoretical topics in quantum optics, quantum physics, and condensed matter physics. Themes of interest include nanophysics, the theory of quantum measurement, quantum information, and statistical physics.

Yonathan Shapir – Professor Shapir’s research is in the fields of theoretical condensed matter physics and statistical mechanics. His work has included critical phenomena in ordered and disordered systems such as spin-glasses and random-field systems, classical and quantum transport in dirty metals and the metal-insulator transition, statistical properties of different polymer configurations, fractal properties of percolation and other clusters, and kinetic models of growth and aggregation.

Stephen Teitel – Professor Teitel uses numerical simulations to study phase transitions and critical phenomena in statistical systems. His most recent work has focused on understanding stress and rheology in models of granular and soft-matter materials near the jamming transition.

### Interdisciplinary Research

The breath of modern condensed matter physics leads naturally to interdisciplinary interactions with many other branches of pure and applied science. At the University, numerous groups in other departments have a close overlap with condensed matter physics. These groups include:

**Chemistry**:

Pengfei Huo – Professor Huo’s research is in physical and theoretical chemistry, including ab-initio dynamics for understanding chemical processes, and the photo physics of solar energy conversion.

Todd Krauss – Professor Krauss’ research concerns colloidal nanoscale semiconductors, carbon nanotubes, and their applications for non-linear optical devices and biological sensors.

**Chemical Engineering:**

Mitchell Anthamatten – Professor Anthamatten’s research in on the self-assemply of macromolecules, associative and functional polymers, nanostructured materials, interfacial phenomena, optoelctronic materials, and vapor deposition polymerization

Eldred Chimowitz – Professor Chimowitz’s interests are in critical phenomena, supercritical fluids, percolation and computer simulations.

Andrew White – Professor White’s research is in materials design, self-assembly, computer simulation and machine learning.

**Mechanical Engineering:**

Niaz Abdolrahim – Professor Abdolrahim’s research uses multiscale modeling of materials and atomistic simulations to study nanoporous materials, nanowires, and thin films.

Hesam Askari - Professor Askari’s research is on the mechanics and rheology of solids, soft matter, granular materials and complex media.

Douglas Kelley – Professor Kelley’s research concerns mixing and transport in fluids, liquid metal batteries, geophysical fluid dynamics and dynamical systems.