Symmetry breaking & Quantum Criticality
In the realm of condensed matter physics, the principle of symmetry breaking serves as a cornerstone, a methodology elegantly formulated by Landau and Ginzburg about a century ago. The potency of this principle has been profound, underpinning a vast array of physical phenomena and providing a successful classification schema for numerous phases of matter across a diverse range of systems. Whether we are examining crystalline structures, ferromagnets, or superconductors, the signatures of symmetry breaking are ubiquitous.
Yet, the story didn’t stop there. The introduction of the renormalization group concept by Kenneth Wilson brought an invaluable tool to the table. By providing a way to connect microscopic laws with macroscopic phenomena, Wilson’s approach further enriched our understanding of phases of matter. With it, we were able to link phase transition critical points to universality and establish low-energy effective theories. This remarkable development evolved the study of phases of matter into what we now refer to as the Landau-Ginzburg-Wilson paradigm.
In the contemporary research landscape, our group is pushing the frontiers of symmetry breaking even further, harnessing modern Atomic, Molecular, and Optical (AMO) platforms. Working in collaboration with experimental groups, we meticulously engineer spontaneous symmetry breaking at an atomic level. One compelling area of investigation for us is continuous symmetry breaking (CSB) in two dimensions. The study of CSB promises to unveil deeper layers of understanding about the characteristics and behaviors of quantum systems.
Alongside this, the discovery of exotic phases of matter, such as high-temperature superconductors and quantum Hall systems, has sparked a renewed interest in examining phase transitions from a quantum perspective. It has become increasingly clear that at absolute zero temperature, quantum fluctuations can drive transitions, leading to the emergent concept of Quantum Phase Transitions (QPTs). QPTs are remarkable, occurring at a critical value of a non-thermal control parameter such as pressure or magnetic field at absolute zero temperature. This profound shift in understanding prompts a wealth of research opportunities.
Our research group delves into key aspects of this topic, with particular focus on quantum critical phenomena and scaling. Furthermore, we study quantum phases induced by quantum fluctuations, such as quantum spin liquids, which represent states of matter that remain magnetically disordered even at absolute zero due to strong quantum entanglement.
In an exciting collaboration with the Kang Kuen Ni group at Harvard, we are utilizing a Rydberg tweezer array platform to investigate the scaling phenomena at the quantum critical point of a system. This exploration is informed by a theoretical framework known as the Ising conformal field theory (CFT), which offers predictions about correlations in the system that adhere to a power law.
In parallel, our research extends to exploring potential quantum spin liquid phases within spin-1 Rydberg atom systems. This system, novel in its nature, provides a fertile ground for studying unique and exotic phases of matter. Our research in this area will contribute significantly to our overall understanding of quantum phase transitions and the intricate roles played by quantum fluctuations.
In sum, the journey from Landau and Ginzburg’s formulation of symmetry breaking to our present-day exploration of quantum criticality and symmetry breaking at an atomic scale exemplifies the ongoing evolution and dynamism in condensed matter physics. It is an exciting time to be on the frontier of these investigations, where new discoveries and advancements are transforming our understanding of the quantum world.