A transverse-field Ising chain featuring dimerised anisotropic Γ interactions has been investigated. Competition between Γ anisotropy and the transverse field exists both without and with Ising interactions. The study analyses vector chiral order alongside dynamical quantum phase transitions within this specific system. Theoretical modelling of the described Ising chain observes these phenomena. Dimerisation impacts the interplay between anisotropy and external fields, leading to new insights into quantum criticality and associated phases. Observations detail vector chirality as an emergent property influenced by competing energies. Numerical analysis supports findings concerning the 528225 model parameters.

Entanglement entropy reveals novel criticality via competing anisotropies and transverse fields

Subsystem entanglement entropy now displays behaviour distinct from standard Ising criticality along a gapless critical line. Previously unattainable due to limitations in identifying such lines without finite-size drift, this departure represents a sharp advance over existing methods used to understand quantum phase transitions and dynamical behaviours in similar systems. Competition between Gamma anisotropy and the applied transverse field induces vector chiral order alongside dynamic quantum phase transitions resulting in both positive and negative chiral phases, as well as a paramagnetic state.

The energy gap analysis revealed that this new critical line lacks finite-size drift when Ising interactions are absent; therefore calculations aren’t skewed by limited sample size. Depending on how quickly parameters were altered during experimentation, sequences describing these dynamical changes can be either predictably periodic or entirely random.

At certain points along this newly identified critical line, low-energy excitations exhibit quadratic behaviour rather than linear responses seen in standard criticality, suggesting fundamentally different dynamics arising from the interplay between anisotropy and field strength. This approach allows detailed investigation into vector chirality, a specific arrangement of spins exhibiting rotational asymmetry, alongside dynamic quantum phase transitions where system properties change abruptly, providing insight into complex magnetic ordering phenomena.

Identifying genuine gapless criticality and vector chirality in the one-dimensional Ising model

Understanding how competing interactions give rise to exotic phenomena continues to drive materials science as we seek ever more sophisticated technologies. Pinpointing truly gapless critical lines, those unaffected by artificial constraints of finite system sizes during modelling, has long been a stumbling block hindering progress within this field. The work establishes a clear pathway for identifying genuinely gapless criticality within the Ising chain framework despite inherent challenges when modelling low-dimensional systems where edge effects can mimic true critical behaviour; it opens possibilities for exploring previously inaccessible regimes of quantum magnetism.

Foshan University researchers have demonstrated that subtle changes to magnetic interactions dramatically alter the behaviour of the transverse field Ising chain, a fundamental quantum system. Their findings reveal that combining competition between Gamma anisotropy, a preference for spin alignment along specific directions, with an external field induces vector chiral order and dynamic shifts in quantum states. Specifically, they identified a gapless critical line where calculations remain accurate regardless of sample size, overcoming longstanding challenges and establishing unique spin correlations and entanglement properties which could unlock new avenues for designing materials with tailored magnetic behaviours.

The research established the presence of vector chiral order and dynamical quantum phase transitions within a transverse-field Ising chain featuring dimerized anisotropic interactions. This is important because it demonstrates how subtle adjustments to magnetic arrangements can significantly influence system behaviour. Researchers successfully pinpointed a gapless critical line unaffected by modelling limitations, allowing them to characterise distinct spin correlations and subsystem entanglement entropy. The authors detailed that this work provides insight into complex magnetic ordering phenomena arising from competing interactions in one-dimensional systems.

👉 More information
🗞 Vector chiral order and dynamical quantum phase transitions in an Ising chain with dimerized anisotropic Gamma interaction
✍️ Yu-Hong Yan, Shi-Qiao Wu and Kun-Liang Zhang (Foshan University)
🧠 ArXiv: https://arxiv.org/abs/2610.01167

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