Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Europhysics Letters (EPL)

A dynamical crossover regime during evanescent-wave amplification

Laura Adams

Published Oct 1, 2013• 3 citations
Publisher

Abstract

\n\nA dynamical crossover regime is revealed when exposing a classical two-dimensional–ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and at the lowest power setting, $-55\\ \\text{dBm}$ , evanescent waves are transmitted without loss and the resonance exhibits a quality factor of ${\\sim}4200$ . A second, smaller resonance, which evolves with increasing power from the main resonance, is also investigated. In contrast to the behavior of the main resonance, this second peak grows as the incident power is increased and does not maintain a fixed resonant frequency for temperatures less than the superconducting critical temperature of niobium. The tunability of both resonances is studied as a function of temperature and microwave power. Finally, we speculate that this dynamical crossover regime is evidence of a transition between two states of phase coherence where at low microwave power the JJ arrays are phase locked and at high microwave power the JJ arrays are unlocked.\n

DOI
10.1209/0295-5075/104/27009

Related papers

A Dynamical Cross-over Regime in the Transmission and Reflection Spectra of Evanescent Waves with 2D Arrays of Josephson Junctions

Laura Adams

A dynamical cross-over regime is revealed when exposing a classical two-dimensional ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and at the lowest power setting, -55 dBm, evanescent waves are transmitted without loss and the resonance exhibits a quality factor of ~ 4200. A second, smaller resonance, which evolves with increasing power from the main resonance, is also investigated. In contrast to the behavior of the main resonance, this second peak grows as the incident power is increased and does not maintain a fixed resonant frequency for temperatures less than the superconducting critical temperature of niobium. The tunability of both resonances is studied as a function of temperature and microwave power. Finally we speculate that this dynamical crossover regime is evidence of a transition between two states of phase coherence where at low microwave power the JJ arrays are phase locked and at high microwave power the JJ arrays are unlocked.

arXiv:1302.4364•Feb 18, 2013•0 citations

Wireless Josephson Junction Arrays as Tunable Metamaterials: Inducing Discrete Frequency Steps with Microwave Radiation

Laura Adams

We report low temperature, microwave transmission measurements on a new switchable and tunable class of nonlinear metamaterials. A wireless two dimensional array of Josephson junctions (JJ) is probed as a metamaterial where each plaquette in the array is considered as a meta-atom. In the presence of microwaves, this compact metamaterial of 30,000 connected meta-atoms synchronizes the flow of Cooper pairs to yield a single robust resonant signal with a quality factor of 2800 at the lowest temperature for our measurements. The transmission signal is switched on and off and its amplitude and frequency are tuned with either temperature, incident rf power or dc magnetic field. Surprisingly, increasing the incident rf power above a threshold causes the resonance to split into multiple discrete resonances that extend over a range of 240 MHz for a wide temperature window. We posit that this effect is a new incarnation of the inverse ac Josephson effect where the Josephson plasma frequency locks to the rf drive frequency generating quantized frequency steps, instead of voltage steps, in the absence of a dc bias.

arXiv:1501.05796•Jan 23, 2015•0 citations

Dynamics of Josephson junction arrays—Microscopic investigations and applications

Thomas Doderer

We discuss the dynamics of two-dimensional arrays of Josephson junctions in the overdamped regime. Our discussion is restricted to “classical” arrays, where the Josephson coupling energy is much larger than the charging energy. Such arrays represent a highly controllable system to study the dynamics of vortices. Furthermore, they are promising for applications like, e.g., a coherent microwave source. The experiments have been performed with arrays of Nb/AlOx/Nb-tunnel junctions allowing a high degree of junction uniformity across the array. The typical array size is 10×10 junctions. We show spatially resolved measurement results obtained by low-temperature scanning electron microscopy, and demonstrate the merit of these investigations for the clarification of complex regimes of vortex dynamics as well as for the optimization of coherent microwave sources. In the case of external microwave irradiation with increasing power, a continuous transition from a non-locked to a completely locked oscillation state is presented. In addition, we report on the quantitative measurement of the emitted microwave power from the arrays.

AIP conference proceedings•Jan 1, 1998•0 citations

Phase locking of Josephson junctions in a two-dimensional array

S. G. Lachenmann, T. Doderer, R. P. Huebener

We studied the behavior of Josephson junctions in a two-dimensional array under the influence of micro-wave irradiation. We are able to distinguish between junctions that are phase locked to the external microwave and unlocked junctions by means of spatially resolving measurements. The degree of coherence in the array can be influenced by tuning the external rf power. Analogies to the coherent behavior of atoms in a laser are pointed out.

Physical review. B, Condensed matter•Jun 1, 1996•9 citations

Quantum and classical resonant escapes of a strongly driven Josephson junction

Hui Yu, X. B. Zhu, Zhihui Peng +9 more

The properties of phase escape in a dc superconducting quantum interference device (SQUID) at 25 mK, which is well below quantum-to-classical crossover temperature ${T}_{cr}$, in the presence of strong resonant ac driving have been investigated. The SQUID contains two $\text{Nb}/{\text{Al-AlO}}_{x}/\text{Nb}$ tunnel junctions with Josephson inductance much larger than the loop inductance so it can be viewed as a single junction having adjustable critical current. We find that with increasing microwave power $W$ and at certain frequencies $\ensuremath{\nu}$ and $\ensuremath{\nu}/2$, the single primary peak in the switching current distribution, which is the result of macroscopic quantum tunneling of the phase across the junction, first shifts toward lower bias current $I$ and then a resonant peak develops. These results are explained by quantum resonant phase escape involving single and two photons with microwave-suppressed potential barrier. As $W$ further increases, the primary peak gradually disappears and the resonant peak grows into a single one while shifting further to lower $I$. At certain $W$, a second resonant peak appears, which can locate at very low $I$ depending on the value of $\ensuremath{\nu}$. Analysis based on the classical equation of motion shows that such resonant peak can arise from the resonant escape of the phase particle with extremely large oscillation amplitude resulting from bifurcation of the nonlinear system. Our experimental result and theoretical analysis demonstrate that at $T⪡{T}_{cr}$, escape of the phase particle could be dominated by classical process, such as dynamical bifurcation of nonlinear systems under strong ac driving.

arXiv:1004.1863•Physical Review B•Apr 28, 2010•29 citations

Measurements of Phase Dynamics in Planar Josephson Junctions and SQUIDs

D. Z. Haxell, Erik Cheah, Filip Křížek +8 more

We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature T^{*} is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, T^{*} is also tuned by a magnetic flux.

arXiv:2204.05619•Physical Review Letters•Feb 23, 2023•22 citations
\n\nA dynamical crossover regime is revealed when exposing a classical two-dimensional–ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and at the lowest power setting, −55textdBm-55\\ \\text{dBm}−55textdBm , evanescent waves are transmitted without loss and the resonance exhibits a quality factor of sim4200{\\sim}4200sim4200 . A second, smaller resonance, which evolves with increasing power from the main resonance, is also investigated. In contrast to the behavior of the main resonance, this second peak grows as the incident power is increased and does not maintain a fixed resonant frequency for temperatures less than the superconducting critical temperature of niobium. The tunability of both resonances is studied as a function of temperature and microwave power. Finally, we speculate that this dynamical crossover regime is evidence of a transition between two states of phase coherence where at low microwave power the JJ arrays are phase locked and at high microwave power the JJ arrays are unlocked.\n
A dynamical cross-over regime is revealed when exposing a classical two-dimensional ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and at the lowest power setting, -55 dBm, evanescent waves are transmitted without loss and the resonance exhibits a quality factor of ~ 4200. A second, smaller resonance, which evolves with increasing power from the main resonance, is also investigated. In contrast to the behavior of the main resonance, this second peak grows as the incident power is increased and does not maintain a fixed resonant frequency for temperatures less than the superconducting critical temperature of niobium. The tunability of both resonances is studied as a function of temperature and microwave power. Finally we speculate that this dynamical crossover regime is evidence of a transition between two states of phase coherence where at low microwave power the JJ arrays are phase locked and at high microwave power the JJ arrays are unlocked.
We report low temperature, microwave transmission measurements on a new switchable and tunable class of nonlinear metamaterials. A wireless two dimensional array of Josephson junctions (JJ) is probed as a metamaterial where each plaquette in the array is considered as a meta-atom. In the presence of microwaves, this compact metamaterial of 30,000 connected meta-atoms synchronizes the flow of Cooper pairs to yield a single robust resonant signal with a quality factor of 2800 at the lowest temperature for our measurements. The transmission signal is switched on and off and its amplitude and frequency are tuned with either temperature, incident rf power or dc magnetic field. Surprisingly, increasing the incident rf power above a threshold causes the resonance to split into multiple discrete resonances that extend over a range of 240 MHz for a wide temperature window. We posit that this effect is a new incarnation of the inverse ac Josephson effect where the Josephson plasma frequency locks to the rf drive frequency generating quantized frequency steps, instead of voltage steps, in the absence of a dc bias.
We discuss the dynamics of two-dimensional arrays of Josephson junctions in the overdamped regime. Our discussion is restricted to “classical” arrays, where the Josephson coupling energy is much larger than the charging energy. Such arrays represent a highly controllable system to study the dynamics of vortices. Furthermore, they are promising for applications like, e.g., a coherent microwave source. The experiments have been performed with arrays of Nb/AlOx/Nb-tunnel junctions allowing a high degree of junction uniformity across the array. The typical array size is 10×10 junctions. We show spatially resolved measurement results obtained by low-temperature scanning electron microscopy, and demonstrate the merit of these investigations for the clarification of complex regimes of vortex dynamics as well as for the optimization of coherent microwave sources. In the case of external microwave irradiation with increasing power, a continuous transition from a non-locked to a completely locked oscillation state is presented. In addition, we report on the quantitative measurement of the emitted microwave power from the arrays.
The properties of phase escape in a dc superconducting quantum interference device (SQUID) at 25 mK, which is well below quantum-to-classical crossover temperature Tcr{T}_{cr}Tcr​, in the presence of strong resonant ac driving have been investigated. The SQUID contains two Nb/Al-AlOx/Nb\text{Nb}/{\text{Al-AlO}}_{x}/\text{Nb}Nb/Al-AlOx​/Nb tunnel junctions with Josephson inductance much larger than the loop inductance so it can be viewed as a single junction having adjustable critical current. We find that with increasing microwave power WWW and at certain frequencies $\ensuremath{\nu}$ and $\ensuremath{\nu}/2$, the single primary peak in the switching current distribution, which is the result of macroscopic quantum tunneling of the phase across the junction, first shifts toward lower bias current III and then a resonant peak develops. These results are explained by quantum resonant phase escape involving single and two photons with microwave-suppressed potential barrier. As WWW further increases, the primary peak gradually disappears and the resonant peak grows into a single one while shifting further to lower III. At certain WWW, a second resonant peak appears, which can locate at very low III depending on the value of $\ensuremath{\nu}$. Analysis based on the classical equation of motion shows that such resonant peak can arise from the resonant escape of the phase particle with extremely large oscillation amplitude resulting from bifurcation of the nonlinear system. Our experimental result and theoretical analysis demonstrate that at T⪡TcrT⪡{T}_{cr}T⪡Tcr​, escape of the phase particle could be dominated by classical process, such as dynamical bifurcation of nonlinear systems under strong ac driving.
We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature T^{*} is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, T^{*} is also tuned by a magnetic flux.