Jun 2021 • Physical Review A

Danko Georgiev, Leon Bello, Avishy Carmi, Eliahu Cohen

EC

Complementarity between one-particle visibility and two-particle visibility in discrete systems can be extended to bipartite quantum-entangled Gaussian states implemented with continuous-variable quantum optics. The meaning of the two-particle visibility originally defined by Jaeger, Horne, Shimony, and Vaidman with the use of an indirect method that first corrects the two-particle probability distribution by adding and subtracting other distributions with varying degree of entanglement, however, deserves further analysis. Furthermore, the origin of complementarity between one-particle visibility and two-particle visibility is somewhat elusive and it is not entirely clear what is the best way to associate particular two-particle quantum observables with the two-particle visibility. Here, we develop a direct method for quantifying the two-particle visibility based on measurement of a pair of two-particle observables that are …

Show moreJun 2021 • ACS Applied Nano Materials

Reut Yemini, Shira Frank, Michal Natan, Gila Jacobi, Hagit Aviv, Melina Zysler, Ehud Banin, Malachi Noked

EB

MN

Jun 2021 • Optical Fiber Communication Conference, F1B. 6, 2021

Hilel Hagai Diamandi, Avi Zadok

AZ

The constituent cores of multi-core fibers are coupled by acoustic modes, guided by the entire cladding cross-section. Acoustic coupling leads to inter core cross phase modulation. The effect is quantified in analysis and experiment.

Show moreJun 2021 • Optics Express

Avi Klein, Sara Meir, Hamootal Duadi, Arjunan Govindarajan, Moti Fridman

MF

We study the polarization dynamics of ultrafast solitons in mode-locked fiber lasers. We find that when a stable soliton is generated, its state of polarization shifts toward a stable state, and when the soliton is generated with excess power levels it experiences relaxation oscillations in its intensity and timing. On the other hand, when a soliton is generated in an unstable state of polarization, it either decays in intensity until it disappears, or its temporal width decreases until it explodes into several solitons, and then it disappears. We also found that when two solitons are simultaneously generated close to each other, they attract each other until they collide and merge into a single soliton. Although these two solitons are generated with different states-of-polarization, they shift their state of polarization closer to each other until the polarization coincides when they collide. We support our findings by numerical calculations of …

Show moreJun 2021 • Nature communications

Eylon Persky, Naor Vardi, Ana Mafalda RVL Monteiro, Thierry C van Thiel, Hyeok Yoon, Yanwu Xie, Benoît Fauqué, Andrea D Caviglia, Harold Y Hwang, Kamran Behnia, Jonathan Ruhman, Beena Kalisky

BK

In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO 3/SrTiO 3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming.

Show moreJun 2021 • Journal of Physics A: Mathematical and Theoretical

Klaus Ziegler, Eli Barkai, David A Kessler

EB

Randomly repeated measurements during the evolution of a closed quantum system create a sequence of probabilities for the first detection of a certain quantum state. The related discrete monitored evolution for the return of the quantum system to its initial state is investigated. We found that the mean number of measurements until the first detection is an integer, namely the dimensionality of the accessible Hilbert space. Moreover, the mean first detected return time is equal to the average time step between successive measurements times the mean number of measurements. Thus, the mean first detected return time scales linearly with the dimensionality of the accessible Hilbert space. The main goal of this work is to explain the quantization of the mean return time in terms of a quantized Berry phase.

Show moreJun 2021 • The Journal of Chemical Physics

Maxim Sukharev, Adi Salomon, Joseph Zyss

AS

We investigate second harmonic generation (SHG) from hexagonal periodic arrays of triangular nano-holes of aluminum using a self-consistent methodology based on the hydrodynamics-Maxwell–Bloch approach. It is shown that angular polarization patterns of the far-field second harmonic response abide to threefold symmetry constraints on tensors. When a molecular layer is added to the system and its parameters are adjusted to achieve the strong coupling regime between a localized plasmon mode and molecular excitons, Rabi splitting is observed from the occurrence of both single- and two-photon transition peaks within the SHG power spectrum. It is argued that the splitting observed for both transitions results from direct two-photon transitions between lower and upper polaritonic states of the strongly coupled system. This interpretation can be accounted by a tailored three-level quantum model, with results …

Show moreJun 2021 • arXiv preprint arXiv:2106.08982

Yoad Michael, Isaac Jonas, Leon Bello, Mallachi-Ellia Meller, Eliahu Cohen, Michael Rosenbluh, Avi Pe'er

MR

EC

AP

Jun 2021 • Photonics

Nathalie Lander Gower, Silvia Piperno, Asaf Albo

AA

We have studied the effect of doping on the temperature performance of a split-well (SW) direct-phonon (DP) terahertz (THz) quantum-cascade laser (QCL) scheme supporting a clean three-level system. Achieving a system that is as close as possible to a clean n-level system proved to be the strategy that led to the best temperature performance in THz-QCLs. We expected to obtain a similar improvement to that observed in resonant-phonon (RP) schemes after increasing the carrier concentration from 3× 10 10 cm− 2 to 6× 10 10 cm− 2. Our goal was to improve the temperature performance by increasing the doping, ideally the results should have improved. To our surprise, in the devices we checked, the results show the contrary. Although an increase in doping had previously shown a positive effect in RP schemes, our results indicated that this does not happen with SW–DP devices. However, we observed a significant increase in gain broadening and a reduction in the dephasing time as the doping and temperature increased. We attribute these effects to enhanced ionized-impurity scattering (IIS). The observation and study of effects related to dephasing included in our experimental work have previously only been possible via simulation. View Full-Text

Show moreJun 2021 • Bulletin of the American Physical Society

Roy Elbaz, Yaakov Yudkin, Lev Khaykovich

LK

H08. 00001: Observation of coherent oscillations in molecular association from ultra cold thermal gasץ

Show moreJun 2021 • Nature communications

Eylon Persky, Naor Vardi, Ana Mafalda RVL Monteiro, Thierry C van Thiel, Hyeok Yoon, Yanwu Xie, Benoît Fauqué, Andrea D Caviglia, Harold Y Hwang, Kamran Behnia, Jonathan Ruhman, Beena Kalisky

BK

In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO 3/SrTiO 3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming.

Show moreJun 2021 • Applied Physics Letters

Ilan Hakimi, Naor Vardi, Amos Sharoni, Michael Rosenbluh, Yosef Yeshurun

MR

We measured the photon count rate (PCR) and dark count rate (DCR) of a superconducting nanowire single photon detector (SNSPD) exposed to either a DC magnetic field (up to 60 mT) or to a low-amplitude oscillating field ( 0.12 – 0.48 mT, up to 50 kHz). In both cases, the results show an increase in the PCR and the DCR as the DC field or the frequency of the AC field increase. However, the ratio DCR/(PCR + DCR) increases significantly with an increasing DC field, whereas this ratio is approximately constant as the frequency of the AC field increases up to frequencies in the kHz regime. The results suggest a more favorable effect of AC fields on the operation of the SNSPD.

Show moreJun 2021 • arXiv preprint arXiv:2106.13085

Itai Orr, Moshik Cohen, Harel Damari, Meir Halachmi, Zeev Zalevsky

ZZ

High resolution automotive radar sensors are required in order to meet the high bar of autonomous vehicles needs and regulations. However, current radar systems are limited in their angular resolution causing a technological gap. An industry and academic trend to improve angular resolution by increasing the number of physical channels, also increases system complexity, requires sensitive calibration processes, lowers robustness to hardware malfunctions and drives higher costs. We offer an alternative approach, named Radar signal Reconstruction using Self Supervision (R2-S2), which significantly improves the angular resolution of a given radar array without increasing the number of physical channels. R2-S2 is a family of algorithms which use a Deep Neural Network (DNN) with complex range-Doppler radar data as input and trained in a self-supervised method using a loss function which operates in multiple data representation spaces. Improvement of 4x in angular resolution was demonstrated using a real-world dataset collected in urban and highway environments during clear and rainy weather conditions.

Show moreJun 2021 • arXiv preprint arXiv:2106.03358

Chenni Xu, Li-Gang Wang, Patrick Sebbah

PS

Chaos, namely exponential sensitivity to initial conditions, is generally considered a nuisance, inasmuch as it prevents long-term predictions in physical systems. Here, we present an easily accessible approach to undo deterministic chaos and tailor ray trajectories in arbitrary two-dimensional optical billiards, by introducing spatially varying refractive index therein. A new refractive index landscape is obtained by a conformal mapping, which makes the trajectories of the chaotic billiard fully predictable and the billiard fully integrable. Moreover, trajectory rectification can be pushed a step further by relating chaotic billiards with non-Euclidean geometries. Two examples are illustrated by projecting billiards built on a sphere as well as the deformed spacetime outside a Schwarzschild black hole, which respectively lead to all periodic orbits and spiraling trajectories in the resulting 2D billiards/cavities. An implementation of our method is proposed, which enables real-time control of chaos and could further contribute to a wealth of potential applications in the domain of optical microcavities.

Show moreJun 2021 • arXiv preprint arXiv:2106.14222

Marc Höll, Eli Barkai

EB

The big jump principle explains the emergence of extreme events for physical quantities modelled by a sum of independent and identically distributed random variables which are heavy-tailed. Extreme events are large values of the sum and they are solely dominated by the largest summand called the big jump. Recently, the principle was introduced into physical sciences where systems usually exhibit correlations. Here, we study the principle for a random walk with correlated increments. Examples are the autoregressive model of first order and the discretized Ornstein-Uhlenbeck process both with heavy-tailed noise. The correlation leads to the dependence of large values of the sum not only on the big jump but also on the following increments. We describe this behaviour by two big jump principles, namely unconditioned and conditioned on the step number when the big jump occurs. The unconditional big jump principle is described by a correlation dependent shift between the sum and maximum distribution tails. For the conditional big jump principle, the shift depends also on the step number of the big jump.

Show moreJun 2021 • 239th ECS Meeting with the 18th International Meeting on Chemical Sensors …, 2021

Lior Elbaz, Andrew M Herring

LE

Jun 2021 • ACS Energy Letters

Amey Nimkar, Fyodor Malchick, Bar Gavriel, Meital Turgeman, Gil Bergman, Tianju Fan, Shaul Bublil, Reut Cohen, Michal Weitman, Netanel Shpigel, Mikhael D Levi, Doron Aurbach

DA

Among the examined organic electrodes for aqueous mono and multivalent ions batteries, polyimide is considered a promising candidate because of its high capacity and good cyclability in different electrolyte solutions. While most of the studies so far were focused on the energetic performance of polyimide anodes, much less is known about their charge storage mechanism and particularly how such electrodes are affected by the solvation properties of the inserted cations. Using in situ EQCM-D, a direct assessment of the cationic fluxes and their hydration shells inserted/extracted to/from PI electrodes upon potential application was performed for a large variety of mono and multivalent cations. Our observations demonstrated a pronounced withdrawal of water molecules from the polymeric electrodes during insertion of chaotropic cations and significantly less water withdrawal upon insertion of kosmotropic cations …

Show moreJun 2021 • arXiv preprint arXiv:2106.00423

Itay Azizi, Yitzhak Rabin

YR

Do solids stabilized by entropy melt with increasing temperature? In order to address this puzzle we use computer simulations to study entropy-driven solidification and melting in binary mixtures of big and small particles interacting via a repulsive potential. At low temperatures and sufficiently large area fractions, big particles form solid clusters stabilized by the osmotic pressure of thesurrounding fluid of small particles. At higher temperatures the solid gradually melts and a homogeneous phase of big and small particles results. We show that increasing temperature enhances the interpenetration and reduces the effective radii of big particles. We argue that the resulting change of balance of free volume and mixing contributions to the entropy is responsible for the melting of the big particle solid. The implications of our results for experiments on asymmetric colloidal mixtures are discussed.

Show moreJun 2021 • Bulletin of the American Physical Society

Yaakov Yudkin, Roy Elbaz, Lev Khaykovich

LK

The interaction strength-dependence of a molecule's binding energy discloses crucial information about the system's interaction potential. In general, a bound state features a plethora of bendings, turns and avoided crossings. Contrarily, universal few-body bound states are insensitive to short-range details of the potential, given that their wave function extends far beyond the characteristic interaction range. Here we use refined, recently proposed few-body spectroscopy [1] to create a coherent superposition of two such universal bound states: Feshbach dimers and Efimov trimers. In an interferometer-like experiment we measure the Efimov binding energy relative to that of the dimer in the theoretically controversial and experimentally demanding regime where the first excited trimer supposedly merges with the dimer-atom continuum. Our results show that the Efimov trimer does not live up to its universal promise [2 …

Show moreJun 2021 • Composites Part B: Engineering 223, 109102, 2021

Weiheng Xu, Sayli Jambhulkar, Yuxiang Zhu, Dharneedar Ravichandran, Mounika Kakarla, Brent Vernon, David G Lott, Jeffrey L Cornella, Orit Shefi, Guillaume Miquelard-Garnier, Yang Yang, Kenan Song

OS

The 3D printing method, alternatively known as additive manufacturing (AM), is promising for rapid tooling and layered micromanufacturing. However, significant fundamental research and applied study in the 3D printing area are still necessary to develop new manufacturing mechanisms for combining multi-materials for multiscale and multi-functionality behaviors. Among those materials, particles with unique mechanical, thermal, electrical, optical, and other functional properties can find broad applications in structural composites, thermal packaging, electrical devices, optoelectronics, biomedical implants, energy storage, filtration, and purification. This review will first briefly cover the 3D printing basics before presenting the critical factors in polymer/particle-based printing. We will then introduce a spectrum of different printing mechanisms, i.e., vat polymerization-based, jetting-based, material extrusion-based …

Show moreJun 2021 • Physical Review A

Yaakov Yudkin, Lev Khaykovich

LK

While Efimov physics in ultracold atoms is usually modeled with an isolated Feshbach resonance, many real world resonances appear in close vicinity to each other and are therefore overlapping. Here we derive a realistic model based on the mutual coupling of an open channel and two closed molecular channels while neglecting short-range physics as permitted by the narrow character of the considered resonances. The model is applied to three distinct scenarios with experimental relevance. We show that the effect of overlapping resonances is manifested most strikingly at a narrow resonance in whose vicinity there is a slightly narrower one. In this system the Efimov ground state extends not only over the scattering length zero crossing between the two resonances but also over the pole of the second resonance to finally meet the dissociation threshold below it. In the opposite scenario, when a narrow …

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