A recent study has unraveled some of the secrets concealed within the entangled web of quantum systems.
In the intricate world of quantum physics, where particles interact in ways that seem to defy the standard rules of space and time, lies a profound mystery that continues to captivate scientists: the nature of deconfined quantum critical points (DQCPs). These elusive critical phenomena break away from the conventional framework of physics, offering a fascinating glimpse into a realm where quantum matter behaves in ways that challenge our classical understanding of the fundamental forces shaping the universe.
A recent study, led by Professor Zi Yang MENG and co-authored by his PhD student Menghan SONG of HKU Department of Physics, in collaboration with researchers from the Chinese University of Hong Kong, Yale University, University of California, Santa Barbara, Ruhr-University Bochum and TU Dresden, has unravelled some of the secrets concealed within the entangled web of quantum systems.
Their findings, recently published in the journal Science Advances, push the boundaries of modern physics and offer a fresh perspective on how quantum matter operates at these enigmatic junctures. The study not only deepens our understanding of quantum mechanics but also paves the way for future discoveries that could revolutionise technology, materials science, and even our understanding of the cosmos.
What are Deconfined Quantum Critical Points?
In everyday life, we are familiar with phase transitions, such as water freezing into ice or boiling into steam. These transitions are well-understood and explained by thermodynamics. However, in the realm of quantum physics, phase transitions can occur at absolute zero temperature (-273.15 °C), driven not by thermal energy but by quantum fluctuations -- tiny, unpredictable movements of particles at the smallest scales. These are known as quantum critical points.
Traditional quantum critical points act as boundaries between two distinct states: a symmetry-broken phase (ordered phase), where particles are neatly arranged, and a disordered phase, where particles are jumbled and chaotic. This kind of transition is well-described by the Landau theory, a framework that has been the foundation of our understanding of phase transitions for decades.
But deconfined quantum critical points (DQCPs) break this mould. Instead of a sharp boundary separating an ordered phase from a disordered phase, DQCPs lie between two different ordered phases, each with its own unique symmetry-breaking pattern, meaning the way particles are arranged or interact in one phase is fundamentally different from the other. This is unusual because, traditionally, phase transitions involve moving from an ordered state to a disorder one, not from one type of order to another. This distinction makes DQCPs fundamentally different and highly intriguing.
Scientists have debated for decades whether DQCPs represent continuous phase transitions (which are smooth and gradual) or first-order transitions (which are sudden and abrupt). Understanding DQCPs could provide new insights into how particles interact and how exotic states of matter emerge.