A new material can be pushed to a quantum breaking point where only one specific type of atom-spin collapses while all the others stay perfectly stable.
April 25, 2026
Original Paper
Field-Induced Selective Spin Gap Closure and Quantum Criticality in BaNd$_2$ZnS$_5$
arXiv · 2604.20173
The Takeaway
Quantum criticality is usually an all-or-nothing event where the entire physical state of a system changes at once. This new research found a material where you can selectively turn off certain parts of the quantum interaction using a magnetic field. This selective breakdown is highly counterintuitive and has never been seen in this way before. It allows scientists to study the moment of quantum collapse in a controlled, surgical manner. Understanding how to break a system apart piece-by-piece could lead to more stable and robust quantum computers that do not fail all at once.
From the abstract
We report thermodynamic evidence for field-induced mode-selective quantum criticality in the layered rare-earth magnet BaNd2ZnS5 (BNZS). Below the Neel temperature TN = 2.9 K, spin-orbit-entangled Nd3+ moments form two symmetry-inequivalent low-energy spin-excitation modes arising from Kramers doublet physics under a magnetic field, with distinct gaps Delta_L and Delta_H. For magnetic fields applied along the [110] direction, the lower-energy gap Delta_L softens continuously and collapses at a c