A team of scientists led by The Hong Kong University of Science and Technology (HKUST) has achieved a major breakthrough by simulating the non-Hermitian skin effect in two dimensions using ultracold fermions. This accomplishment represents a significant step forward in the field of quantum physics.
Quantum mechanics traditionally focuses on systems that are isolated from their environment. It explains a wide range of phenomena, from how electrons behave in solids to how information is processed in quantum devices. These systems are typically described using a Hermitian model (Hamiltonian), which ensures observable properties like energy have real values and remain conserved.
Understanding Non-Hermitian Dynamics
However, when a quantum system interacts with its surroundings—exchanging particles or energy—the Hermitian model breaks down. Instead, such open systems are better described by a non-Hermitian Hamiltonian. This approach has unlocked new insights into quantum information, curved space, unusual topological phases, and even the physics of black holes. Yet, many mysteries about non-Hermitian quantum behavior, particularly in higher dimensions, remain unresolved.
In collaboration with Peking University (PKU), physicists from the two universities have simulated one such intriguing phenomenon—the non-Hermitian skin effect (NHSE)—which involves the accumulation of eigenstates at the boundary of an open system. This successful demonstration marks a crucial advancement, as previous experimental realizations of the non-Hermitian skin effect were limited to lower dimensions or classical systems rather than quantum systems.
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