2026-10-14T13:58:42Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33158033 2026-09-29T04:04:24Z category_30235 category_30238 category_30136 category_30181 item_type_12 month_year_09_2026

Floquet-Engineered Superradiant Quantum Sensing via Stroboscopic Liouvillian Control Francis Procaccia (24515003) Quantum optics and quantum optomechanics Quantum technologies Atomic, molecular and optical physics not elsewhere classified Condensed matter physics not elsewhere classified Floquet Engineering Dicke Model superradiant phase transition Cavity Quantum Electrodynamics Bose–Einstein Condensate Quantum Metrology quantum Fisher information Liouvillian spectral gap Non-equilibrium quantum sensing Resource-fair quantum control <p dir="ltr">We propose a stroboscopic Floquet sensing protocol that applies periodic coherent displacement kicks to a cavity–Bose-Einstein condensate system operated in the normal phase near the Dicke superradiant critical point. The kicks do not alter the underlying Hamiltonian or dissipation rates, yet they produce a stroboscopic steady state with a period-dependent Fisher information that exhibits a bounded maximum at an optimal strobe period (T^*).Two complementary theoretical pictures are developed. In the linearized Gaussian model, the enhancement arises from stroboscopic resonance at (T^* \approx 2\pi/\omega_0). In the full Lindblad treatment, noncommutativity between the Liouvillian and the kick generator generates Baker-Campbell-Hausdorff corrections. After projection onto the slow mode, these corrections renormalize the effective gap in the intermediate-period regime. Numerical fits support the local behavior[\mu(T) \approx \mu_0 + \frac{a}{T^2} + cT^2,\qquad a<0,;c>0.]This produces an optimal sensing period determined by competition between the two terms.Numerical simulations at moderate truncation levels ((N=3\text{–}5)) with a displacement kick yield a Fisher information gain of (\times4.5\text{–}5.0) relative to the static case. However, a higher-truncation benchmark at (N=11) using a squeezing kick shows no detectable enhancement. That benchmark simultaneously changes the kick type, the coupling (g/\kappa), and the kick strength (\epsilon) relative to the (N\leq5) runs, and therefore does not isolate a truncation effect.As shown in Sec. 4.3, the squeezing null is instead a first-moment sector effect that does not depend on truncation: the enhancement resides entirely in the stroboscopic mean[R^*(T)=\left(I-e^{AT}\right)^{-1}d](Appendix A). A squeezing kick contributes no affine displacement ((d=0)), so the corresponding homodyne Fisher information vanishes identically.The displacement-kick gains are shown to be exactly truncation-converged (Sec. 4.4) and therefore represent robust finite-(N) enhancements. In the thermodynamic limit (N\rightarrow\infty) at fixed (g/\sqrt{N}), the enhancement decays as a power law. The protocol is therefore best understood as a finite-size resonance rather than a thermodynamic-limit divergence.The protocol offers a route to sensing enhancement without operating at the critical point or requiring feedback. Its performance is highly sensitive to the choice of kick operator, highlighting both the promise and the practical limits of Floquet control for quantum metrology.</p> 2026-09-29T04:04:24Z Text Preprint 10.6084/m9.figshare.33158033.v5 https://figshare.com/articles/preprint/Floquet-Engineered_Superradiant_Quantum_Sensing_via_Stroboscopic_Liouvillian_Control/33158033 CC BY 4.0