Preprint arXiv: 2208.10487 Submitted on 22 Aug 2022

The physics of long-range interacting quantum systems is currently living a renaissance driven by the fast progress in quantum simulators. In these systems many paradigms of statistical physics do not apply and also the universal long-wavelength physics gets substantially modified by the presence of long-ranged forces. Here we explore the low-energy excitations of several long-range interacting quantum systems, including spin models and interacting Bose gases, in the ordered phase associated with the spontaneous breaking of U(1) and SU(2) symmetries. Instead of the expected Goldstone modes, we find three qualitatively different regimes, depending on the range of the interaction. In one of these regimes the Goldstone modes are gapped, via a generalization of the Higgs mechanism. Moreover, we show how this effect is realized in current experiments with ultracold atomic gases in optical cavities

Floquet-Engineered Nonlinearities and Controllable Pair-Hopping Processes: From Optical Kerr Cavities to Correlated Quantum Matter

This work explores the possibility of creating and controlling unconventional nonlinearities by periodic driving, in a broad class of systems described by the nonlinear Schrödinger equation (NLSE). By means of a parent quantum many-body description, we demonstrate that such driven systems are well captured by an effective NLSE with emergent nonlinearities, which can be finely controlled by tuning the driving sequence. We first consider a general class of two-mode nonlinear systems—relevant to optical Kerr cavities, waveguides, and Bose-Einstein condensates—where we find an emergent four-wave mixing nonlinearity, which originates from pair-hopping processes in the parent quantum picture. Tuning this drive-induced nonlinearity is shown to modify the phase-space topology, which can be detected through relative population and phase measurements, and also leads to enhanced quantum properties such as spin squeezing. We then couple individual (two-mode) dimers in view of designing extended lattice models with unconventional nonlinearities and controllable pair-hopping processes. Following this general dimerization construction, we obtain an effective lattice model with drive-induced interactions, whose ground state exhibits orbital order, chiral currents, and emergent magnetic fluxes through the spontaneous breaking of time-reversal symmetry. We analyze these intriguing properties both in the weakly interacting (mean-field) regime, captured by the effective NLSE, and in the strongly correlated quantum regime. Our general approach opens a route for the engineering of unconventional optical nonlinearities in photonic devices and controllable drive-induced interactions in ultracold quantum matter

Significant papers from the First 25 Years of the FPL Conference

The list of significant papers from the first 25 years of the Field-Programmable Logic and Applications conference (FPL) is presented in this paper. These 27 papers represent those which have most strongly influenced theory and practice in the field.postprin

Dutch modality exclusivity norms : Simulating perceptual modality in space

Perceptual information is important for the meaning of nouns. We present modality exclusivity norms for 485 Dutch nouns rated on visual, auditory, haptic, gustatory, and olfactory associations. We found these nouns are highly multimodal. They were rated most dominant in vision, and least in olfaction. A factor analysis identified two main dimensions: one loaded strongly on olfaction and gustation (reflecting joint involvement in flavor), and a second loaded strongly on vision and touch (reflecting joint involvement in manipulable objects). In a second study, we validated the ratings with similarity judgments. As expected, words from the same dominant modality were rated more similar than words from different dominant modalities; but - more importantly - this effect was enhanced when word pairs had high modality strength ratings. We further demonstrated the utility of our ratings by investigating whether perceptual modalities are differentially experienced in space, in a third study. Nouns were categorized into their dominant modality and used in a lexical decision experiment where the spatial position of words was either in proximal or distal space. We found words dominant in olfaction were processed faster in proximal than distal space compared to the other modalities, suggesting olfactory information is mentally simulated as "close" to the body. Finally, we collected ratings of emotion (valence, dominance, and arousal) to assess its role in perceptual space simulation, but the valence did not explain the data. So, words are processed differently depending on their perceptual associations, and strength of association is captured by modality exclusivity ratings

Proceedings - IEEE 25th Annual International Symposium on Field-Programmable Custom Computing Machines, FCCM 2017

© 2017 IEEE. Field-Programmable Gate Arrays (FPGAs) are susceptible to radiation-induced Single Event Upsets (SEUs). A common technique for dealing with SEUs is Triple Modular Redundancy (TMR) combined with Module-based configuration memory Error Recovery (MER). By triplicating components and voting on their outputs, TMR helps localize the configuration memory errors, and by reconfiguring the faulty component, MER swiftly corrects the errors. However, the order in which the voters of TMR components are checked has an inevitable impact on the overall system reliability. In this paper, we outline an approach for computing the reliability of TMR-MER systems that consist of finitely many components. Using the derived reliability models we demonstrate that the system reliability is improved when the critical components are checked more frequently for the presence of configuration memory errors than when they are checked in round-robin order. We propose a genetic algorithm for finding a voter checking schedule that maximizes system reliability for systems consisting of finitely many TMR components. Simulation results indicate that the mean time to failure of TMR-MER systems can be increased by up to 100% when Variable-Rate Voter Checking (VRVC) rather than round robin, is used. We show that the power used to eliminate configuration memory errors in an exemplar TMR-MER system employing VRVC is reduced while system reliability remains high. We also demonstrate that errors can be detected 30% faster on average when the system employs VRVC instead of round robin for voter checking

Fault recovery time analysis for coarse-grained reconfigurable architectures

Coarse-grained reconfigurable architectures (CGRAs) have drawn increasing attention due to their performance and flexibility advantages. Typically, CGRAs incorporate many processing elements in the form of an array, which is suitable for implementing spatial redundancy, as used in the design of fault-tolerant systems. This article introduces a recovery time model for transient faults in CGRAs. The proposed fault-tolerant CGRAs are based on triple modular redundancy and coding techniques for error detection and correction. To evaluate the model, several kernels from space computing are mapped onto the suggested architecture. We demonstrate the tradeoff between recovery time, performance, and area. In addition, the average execution time of an application including recovery time is evaluated using area-based error-rate estimates in harsh radiation environments. The results show that task partitioning is important for bounding the recovery time of applications that have long execution times. It is also shown that error-correcting code (ECC) is of limited practical value for tasks with long execution times in high radiation environments, or when the degree of task partitioning is high