# Quantum Information

### Overview

Quantum Information (QI) aims to exploit the nonclassical properties of quantum systems, particularly entanglement, to surpass fundamental computing limits as defined by classical physics and information theory. For example, QI can enable exponential speedups of quantum computing (Shor) and quantum simulation (Feynman) relative to their classical analogs. QI defines the frontier of study and applications in the very foundations of modern physics. The Physics Department features highly visible research programs in theoretical and experimental QI.

Professor Israel Klich studies theoretical limits on the possible entanglement present in many body systems, among these he has discovered the most entangled spin chain model known to date, and general connections between condensed matter physics observables and multipartite entanglement, leading to its possible measurement. Professor Jones investigates implementations of quantum information in atomic physics, including quantum error correction, decoherence suppression, and novel probes of coherence in Rydberg atom ensembles. Professor Pfister’s research group in quantum optics boasts the largest multipartite entangled cluster state (a quantum state specifically tailored for quantum computing) with 60 qu-modes (continuous-variable qu-bits) in the single light beam emitted by an exotic optical parametric oscillator. Professors Klich and Pfister are also collaborating on the quantum optical simulation of intractable condensed matter systems.

### Personnel

Much of the current research in atomic physics focuses on the use of extremely well-controlled electromagnetic fields to coherently manipulate the internal and external degrees of freedom of atoms. Jones and his students use lasers to cool and trap atoms, to spin molecules in order to align their axes along a particular direction in the laboratory, and to drive electrons within atoms and molecules in particular directions at specific times. These optical techniques serve as tools which allow them to view very fast processes within atoms and molecules and to perform experiments exploring ... More>

My main field of interest is condensed matter physics with strong overlaps with mathematical physics and field theory. My research interests include entanglement in many-body systems, the Casimir effect, topological order and non-equilibrium statistical mechanics. More>

Olivier Pfister’s research focuses on experimental quantum optics and quantum information. The quantum nature of light (the existence of photons) is a fascinating subject which has turned into a mature experimental field since its inception in the eighties. The research by Pfister’s group, “Quantum Fields and Quantum Information” (QFQI), aims at blazing new trails into the realm of quantum information. In particular, QFQI and their theory collaborators, Nicolas Menicucci and Steven Flammia at the University of Sydney, discovered a new, highly scalable experimental ... More>