Ground-state spin squeezing, a resource for quantum-enhanced measurements, often links to a closing excitation gap near a critical point; however, this research identifies conditions where stronger squeezing occurs alongside an *increase* in both collective and many-body gaps. Using models of interacting spins, the team pinpointed specific interaction types that allow for improved squeezing without compromising thermal robustness. This work reveals a surprising link between spin squeezing, a technique enhancing quantum measurement precision, and energy gaps within materials.

The team discovered that stronger spin squeezing can occur alongside *increases* in these key energy gaps; previously thought to be mutually exclusive. This finding identifies specific interactions which improve stability while simultaneously boosting sensitivity for applications like advanced sensors and faster creation of delicate quantum states. The team’s research challenges a long-held assumption that stronger spin squeezing, akin to carefully organizing marbles so they all point in one direction, this alignment enhances sensitivity but is easily disrupted, requires a reduction in energy gaps within materials.

They discovered instances where increased squeezing coincided with *larger* collective and many-body excitation gaps; imagine pushing a ball over a hill, the “gap” represents how much effort it takes to get the system rolling (or excite it), meaning greater stability. Using models of interacting spins, researchers pinpointed interactions which improve both quantum measurement precision and thermal robustness.

This finding has implications for developing advanced sensors and accelerating the creation of delicate quantum states through techniques like adiabatic preparation, similar to slowly tilting a table to slide an object into place without causing it to tumble. But can these beneficial effects be consistently achieved across different material types.

Squeezing reveals counterintuitive links between excitation gaps and thermal stability

Ground-state squeezing now demonstrates improvement: analysis of nearest-neighbour interactions confirmed a “negative-coupling branch” where collective and many-body excitation gaps coincide and increase as squeezing improves, a result previously considered impossible in comparable systems. This gap-opening configuration retains squeezing at higher temperatures than traditional “gap-closing” branches, enhancing its durability against heat, which potentially allows faster adiabatic state preparation for quantum technologies. The anisotropic Lipkin, Meshkov, Glick model and XXZ chains established an exact relationship between spin squeezing, polarization, and weighted excitation energies to pinpoint how fluctuation costs determine these effects.

These findings explain why stronger squeezing can occur alongside either closing or opening energy gaps, challenging long-held assumptions about their inverse correlation within materials. Enhanced thermal robustness could accelerate adiabatic state preparation in quantum technologies by allowing more time to reach the desired final state without losing coherence; this is a significant advantage when building complex systems. Further investigation explores limitations of this effect, while it improves stability on one interaction branch, its broad applicability remains unclear, understanding whether benefits consistently replicate across diverse physical systems represents a key next step.

Squeezed states exhibit enhanced thermal stability under limited spin interaction models

Establishing a pathway towards more stable squeezed states is important for improving precision measurements like those used in advanced sensors, but immediate use remains an open question. Current findings hold strongest for nearest-neighbour interactions within specific models of interacting spins and raise questions about how widely applicable this gap-opening behaviour will prove to be or if it can be replicated across different parameter ranges. Despite uncertainty regarding broad applicability across all physical systems, these findings represent a valuable step forward for precision sensing technologies.

Specific conditions were identified where squeezing enhances sensitivity at higher temperatures than previously thought due to increased energy gaps between states, potentially reducing the need for expensive cooling systems. Maintaining freezing environments adds cost and complexity to quantum devices offering potential benefits; therefore, this discovery could allow wider deployment of this technology in the future.

By modelling interacting spins using theoretical frameworks like the anisotropic Lipkin-Meshkov-Glick model and XXZ chains, researchers pinpointed specific conditions where stronger squeezing coincides with *larger* many-body excitation gaps rather than smaller ones. This challenges assumptions about system stability and opens new avenues for designing quantum systems that are both sensitive and strong against environmental noise, suggesting a path toward overcoming previous trade-offs between sensitivity and durability.

Researchers discovered a relationship between squeezed states, useful for precision measurement, and the energy gap separating different quantum states within certain spin interaction models. Their work demonstrates that increased squeezing can occur alongside larger excitation gaps, which contrasts with typical expectations of reduced thermal robustness when approaching critical points.

Using theoretical frameworks like the anisotropic Lipkin, Meshkov, Glick model and XXZ chains, they found this effect is particularly pronounced in systems with nearest-neighbor interactions and may allow for more stable operation at higher temperatures. The authors plan to investigate whether these benefits extend beyond the specific conditions tested here.

👉 More information
🗞 Ground-State Spin Squeezing and Collective Excitations in $\mathbb{Z}_2$ -Symmetric Systems
✍️ Arkadiusz Kosior,1, 2 George Mihailescu,3, 4 and Karol Gietka 2, ∗
🧠 ArXiv: https://arxiv.org/abs/2611.16738

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