INSTITUTE FOR QUANTUM INFORMATION AND MATTER
PROJECT OUTCOMES REPORT 2018-2024

The Institute for Quantum Information and Matter (IQIM) is an NSF Physics Frontiers Center at the California Institute of Technology established in 2011. Through the collaborative efforts of theorists and experimentalists, we investigate exotic collective phenomena which amplify the weirdness of the quantum world to macroscopic scales. Our research programs span quantum information science, quantum matter, quantum optics, and atomic physics, with faculty drawn from Caltech's departments of physics, applied physics, computer science, electrical engineering, materials science, and chemistry. IQIM also conducts outreach programs to introduce K-12 students and the general public to the wonders of the quantum world, as well as programs targeting undergraduate students that aim to broaden the pipeline of under-represented groups applying to graduate school in STEM fields.

MAJOR RESEARCH THRUSTS
The IQIM encompasses three Major Activities (MAs) enumerated below, but the boundaries between these activities are porous and loosely defined. The MAs reinforce one another, and much of our scientific success has been derived from the interactions among the MAs.

MA-1: Quantum Information Physics, connecting ideas drawn from computer science, information theory, engineering, and mathematics to experimental quantum information platforms such as superconducting circuits, ultracold atoms, and electron spins. MA-1 explores the interface of quantum physics with computer science and information theory, including quantum algorithms, quantum error correction, quantum communication, and entanglement theory. Another focus is the development of potentially scalable platforms for quantum information processing and quantum networking.

MA-1 achievements during this award period include: A highly efficient method for extracting a "classical shadow" of a quantum many-body system using very few local measurements, which can be used to estimate many properties of the system with rigorous performance guarantees. A proof that a classical party interacting with two entangled quantum systems can efficiently check solutions that are undecidable by Turing machines, refuting long-standing mathematical conjectures. Record high fidelities for single-atom readout, single-atom operations, and two-atom entanglement in alkaline-earth Rydberg atom tweezer arrays. The first demonstration of quantum information storage in a nuclear ensemble spin wave.

MA-2: Topological Quantum Physics, spanning a wide variety of topological phenomena in many-particle systems, and particularly emphasizing the prospects for topologically protected quantum information processing. This effort focuses on the emergent phenomena that arise in many-particle quantum systems, including topological phases of matter exhibiting long-range entanglement and charge fractionalization (as in the fractional quantum Hall effect), symmetry-protected topological phases with exotic surface physics (as in topological insulators), and exotic phases of correlated electron systems (such as high-temperature superconductors and twisted bilayer graphene).

MA-2 achievements during this award period include: Realization of correlation-driven topological phases in magic-angle twisted bilayer graphene. Observation of topologically protected edge states in superconducting metamaterial waveguides. Proposals for experimentally realizing Kitaev spin liquids using Rydberg atom tweezer arrays. A new theoretical framework for classifying fracton topological order in three dimensions.

MA-3: Quantum Dynamics, focusing on information scrambling in quantum many-body systems, dynamics of localized quantum phases, and ephemeral quantum phases of matter.  Inspired by concepts from quantum information theory, and armed with highly engineerable physical systems, this activity aims to develop robust methods for preparing states far from equilibrium in open, driven quantum many-body systems, and to explore the dynamics and applications of these exotic new phases of matter.

MA-3 achievements during this award period include: Observation of out-of-equilibrium critical dynamics in an optically driven Mott antiferromagnet. Development of nano-acoustic cavities with ultralong phonon lifetimes. A benchmarking protocol estimating many-body fidelity during chaotic evolution, demonstrated using a Rydberg quantum simulator. Theoretical demonstrations of many-body localization behavior without the need for disorder.

EDUCATION, OUTREACH, DIVERSITY
IQIM provides a multidisciplinary research environment for students (including undergraduates) and postdocs, and organizes activities to enhance the cohesion of the PFC and encourage discussion and collaboration. Many IQIM alumni move on to leadership positions in academia and industry, solidifying the US technical base in quantum science and technology. Another important aspect of our broader impact is a vibrant visitors program, which fuels intellectual excitement, facilitates collaborations and exchanges of scientific ideas, and performs a highly valued service for the international quantum science community.

Aside from our research activities, IQIM also runs a very active and successful outreach program, which draws on technology and media to reimagine and redefine scientific communication and public engagement. Outreach projects during this award period included development of the games Quantum TiqTaqToe and Quantum Chess; the latter now runs on quantum hardware developed in partnership with Google. IQIM also participates heavily in QuanTime, a national educational partnership developing materials that expose K-12 learners to quantum science. A major goal of our outreach program is to improve the pipeline of women and underrepresented minorities entering STEM careers.

Last Modified: 07/02/2024
Modified by: John P Preskill