arXiv subjects

Daniel K. J. Boneß

Publications and source records attributed to Daniel K. J. Boneß.

4 recordsLinked to original sources

arXiv2026

Extracting higher-order nonlinearities in nanomechanical resonators using the backbone relation

Nanomechanical resonators are a powerful platform for studying nonlinear dynamics with high sensitivity and precision. We explore the nonlinear response of a high-Q nanomechanical string resonator in and beyond the Duffing regime and introduce a robust framework for accurately extracting its conservative nonlinearities. The method is based on the backbone curve obtained from ringdown measurements, making it inherently resilient to small frequency fluctuations while explicitly accounting for both symmetry-breaking and non-symmetry-breaking nonlinearities. To validate the approach, we perform complementary ringdown and frequency-response measurements on the nanostring resonator and benchmark the backbone-based extraction against established frequency-response techniques. The comparison confirms the accuracy of the proposed framework and demonstrates its advantages over conventional methods for nonlinear characterization.

cond-mat.mes-hall↗

arXiv2026

Nonequilibrium Kramers Turnover in a Kerr Parametric Oscillator

Activation processes govern noise-induced switching between long-lived states. In an equilibrium double well, the thermally activated switching rate exhibits a prefactor with a nonmonotonic dependence on environmental coupling, a foundational crossover known as Kramers turnover. Here, we demonstrate a Kramers turnover analogue in a Kerr parametric oscillator, a driven-dissipative nonlinear system featuring two stable phase states. First, we analytically establish turnover physics in this out-of-equilibrium setting. There, the strong physical correlation between the activation barrier and intrinsic damping fundamentally obscures the underlying turnover physics. To overcome this limitation, we rescale the rotating-frame dynamics and introduce a tunable effective friction controlled entirely by the parametric drive. This rescaling comes at the cost of a concurrent rescaling of the effective temperature. Exploiting this simultaneous scaling, we leverage the effective temperature to extract the turnover directly from temperature-dependent observations. Subsequently, measuring noise-induced phase slips in a micro-electromechanical device, we observe a distinct crossover in the prefactor's temperature dependence. Our results unambiguously isolate the out-of-equilibrium turnover regime and highlight that the competition between dissipation and fluctuations profoundly shapes activation dynamics also beyond equilibrium.

cond-mat.mes-hall↗

arXiv2026

Spectroscopy of Quantum Phase Slips: Visualizing Complex Real-Time Instantons

Parametrically driven oscillators can emerge as a basis for the next generation of qubits. Classically, these systems exhibit two stable oscillatory states with opposite phases. Upon quantization, these states turn into a pair of closely spaced Floquet states, which can serve as the logical basis for a qubit. However, interaction with the environment induces phase-slip events which set a limit on qubit coherence. Such phase slips persist even at zero temperature due to a mechanism known as quantum activation \cite{QuantumActivation}. In contrast to conventional tunneling, the quantum activation is described by a {\em real-time} instanton trajectory in the complexified phase space of the system. In this work, we show that the phase-slip rate is exponentially sensitive to weak AC perturbations. The spectrum of the system's response -- captured by the so-called logarithmic susceptibility (LS) -- enables a direct observation of characteristic features of real-time instantons. Studying this spectrum suggests new means of efficient qubit control.

quant-ph↗

arXiv2025

Zero-temperature phase-flip rate in a biased parametric oscillator

A parametrically driven oscillator has two stable vibrational states at half the modulation frequency. The states have opposite phase and equal amplitudes. An extra drive at half the modulation frequency provides an effective bias that lifts the state symmetry. Quantum fluctuations lead to switching between the states, i.e., to phase-flip transitions. We develop a semiclassical approach that allows us to find the dependence of the switching rates on the amplitude of the bias and the parameters of the modulating field. We find that the rate of switching from a ''shallow'' state can become anomalously small at certain parameter values, leading to an efficient localization in this state. This is a consequence of the change of the topology of the oscillator phase trajectories. The results pave the way for implementing nonreciprocal quantum Ising systems based on parametric oscillators.

quant-ph↗