arXiv subjects

Moty Heiblum

Publications and source records attributed to Moty Heiblum.

At least 19 recordsLinked to original sources

arXiv2026

Observation of Time-Domain Braiding of Non-Abelian Anyons at $\nu = 5/2$ State

Unlike elementary particles, which obey either bosonic or fermionic exchange statistics, certain quasiparticles, known as anyons, are predicted to exhibit Abelian or non-Abelian braiding statistics. While braiding Abelian anyons modifies the wavefunction by a 'statistical phase', braiding non-Abelian anyons implements a unitary transformation of the state within a degenerate subspace of states. Experimental evidence of non-Abelian braiding has thus far remained elusive. Here, we report a 'time-domain braiding' signature of non-Abelian anyons in the $\nu = 5/2$ fractional quantum Hall state, by extending our previously demonstrated approach with Abelian anyons at $\nu = 1/3$. Our approach is based on measurements of the current fluctuations arising from weak partitioning of a highly dilute one-dimensional edge mode. We independently probe the partition noise of the downstream charged mode and also that of the upstream neutral mode. These independent measurements agree with our theoretical predictions for 'time-domain braiding' of the downstream Abelian and the upstream non-Abelian anyons, respectively, in the 'particle-hole Pfaffian' topological order. Together, these results provide evidence for the presence of non-Abelian anyons.

cond-mat.mes-hall↗

arXiv2026

Surface-Selective Probe of Spin-Triplet Superconductivity in Rhombohedral Graphene

Superconductivity in rhombohedral graphene has been observed across many layer numbers, with mounting evidence pointing toward spin-triplet pairing, yet complementary probes of the superconducting spin structure remain needed. Here we use one-sided WS$_2$ proximity in rhombohedral pentalayer graphene (R5G) as a surface-selective spin-orbit probe. The induced Ising spin-orbit coupling is strongest for carriers localized near the WS$_2$ interface, allowing the displacement field to tune the overlap between superconducting carriers and the spin-orbit perturbation. We observe a strongly asymmetric superconducting landscape: two robust pockets, SC1 and SC2, survive only on mutually opposite signs of displacement field, while a third pocket, SC3, is substantially weaker. Gate-tracking features, quantum oscillations, and self-consistent band-structure calculations identify the layer polarization and Fermi-surface character of the relevant carriers. The robust superconducting states are absent or strongly weakened when the active high-DOS carriers are polarized toward the WS$_2$ interface. Since Ising spin-orbit coupling is compatible with time-reversed spin-singlet pairing but competes with same-spin intervalley triplet pairing by canting or pinning the parent spin texture, this surface-selective suppression provides additional evidence for spin-triplet superconductivity involving both hole-like and electron-like carriers. Our results establish one-sided TMD proximity as a displacement-field-tunable probe of superconducting spin structure in rhombohedral graphene.

cond-mat.mes-hall↗

arXiv2026

Competing Orders Driven by Wigner Crystal Phase in Rhombohedral Graphene

Rhombohedral graphene systems provide a unique platform where strong electronic interactions and nontrivial band topology coexist at low carrier densities and high displacement fields, giving rise to a rich landscape of emergent electronic phases. Here, we report that the highly insulating state on the low-density side of chiral superconductivity in rhombohedral pentalayer graphene (R5G) corresponds to a Wigner crystal (WC) phase. In addition, a hole-doped metallic Wigner crystal (h-mWC) phase emerges near the WC boundary. Under an out-of-plane magnetic field, the system hosts competing magnetic-field-stabilized superconductivity (fSC) and unconventional reentrant quantum Hall (RIQH) states. These emergent phases are closely connected to the underlying WC and mWC states and evolve continuously across phase boundaries. Our results establish that WC phase plays an important role in the phase diagram of rhombohedral multilayer graphene and highlight its connection to a rich landscape of emergent phases.

cond-mat.mes-hall↗

arXiv2026

Constriction-induced modulation of charging energy in a quantum Hall cavity

Electronic Fabry-Pérot interferometers (FPIs) operating in the fractional quantum Hall regime are a key platform for probing anyonic braiding statistics, yet interpreting their interference signals is complicated by Coulomb charging effects, which are commonly treated as parasitic, static properties governed by the cavity's geometry and electrostatics. Here, using a gate-defined quantum Hall cavity tuned to the Coulomb-dominated regime, we demonstrate that the charging energy is in fact strongly and non-monotonically modulated by the magnetic field, varying by up to 60% over a range of only 100 mT. The effect appears exclusively when the quantum point contacts (QPCs) forming the cavity are weakly pinched off, i.e., in the strong cavity-to-lead coupling regime. By correlating the charging energy modulation with the QPC magneto-conductance, we attribute this behavior to field-dependent changes in local compressibility and electrostatic screening between the cavity and the leads, driven by the formation of incompressible fractional quantum Hall states within the constrictions. This result establishes QPC constrictions of quantum Hall cavities as active electrostatic elements rather than passive boundaries, revealing a dynamic screening mechanism, with direct consequences for the interpretation of interference measurements and the extraction of anyonic statistics.

cond-mat.mes-hall↗

arXiv2026

Observation of e/4 charge at $ν=1/2$ in GaAs

Even-denominator fractional quantum Hall states (FQHSs) fall outside the standard Laughlin's and Jain's odd-denominator hierarchy. In this work, we study the FQHS $ν=1/2$ in the lowest Landau level. The state is confined within a 70 nm-wide GaAs quantum well, where the electrons exhibit a bilayer-like charge distribution. Inter-layer interactions stabilize the $ν=1/2$ FQHS, which is predicted to host quasiparticles with charge e/4 - with either Abelian or non-Abelian topological order. Here, we report on shot-noise measurements of partitioned quasiparticles at $ν=1/2$, where charge partitioning is generated by a unique etch-defined quantum point contact. Our measurements were performed on two nominally identical devices, at two independent experimental setups. Analysis of shot noise in the weak-backscattering regime in each device reveals quasiparticles with charge e/4. These observations provide a clear benchmark for future studies aimed at probing the topological order of the $ν=1/2$ FQHS and its quasiparticles' exchange statistics.

cond-mat.mes-hall↗

arXiv2025

Anyonic Braiding in a Chiral Mach-Zehnder Interferometer

Fractional quantum statistics are the defining characteristic of anyons. Measuring the phase generated by an exchange of anyons is challenging, as standard interferometry setups -- such as the Fabry-Pérot interferometer -- suffer from charging effects that obscure the interference signal. Here, we present the observation of anyonic interference and exchange phases in an optical-like Mach-Zehnder interferometer based on co-propagating interface modes. By avoiding backscattering and deleterious charging effects, this setup enables pristine and robust Aharonov-Bohm interference without any phase slips. At various fractional filling factors, the observed flux periodicities agree with the fundamental fractionally charged excitations that correspond to Jain states and depend only on the bulk topological order. To probe anyonic statistics, we use a small, charged top-gate in the interferometer bulk to induce localized quasiparticles without modifying the Aharonov-Bohm phase; however, with introducing periodic phase slips. The magnitude of the observed phase slips and their signs align with the expected value at filling 1/3, but their direction shows systematic deviations at fillings 2/5 and 3/7. Control over added individual quasiparticles in this design is essential for measuring the coveted non-Abelian statistics in the future.

cond-mat.mes-hall↗

arXiv2025

Coherent Bunching of Anyons and their Dissociation in Interference Experiments

Aharonov-Bohm (AB) interference of fractional quasiparticles in the quantum Hall Effect generally reveals their elementary charge ($e^*$)[1-15]. Recently, our interferometry experiments with several particle states reported flux periods of $ΔΦ=(e/e^*)Φ_0$ the flux quantum) at moderate temperatures[16]. Here, we report interference measurements of particle-hole conjugated states at filling factor $ν=2/3, 3/5, 4/7$, revealing unexpected flux periodicities of $ΔΦ=Φ_0/ν$. The measured shot noise Fano factor (F) of the partitioned quasiparticles in each of the interferometers quantum point contacts (QPCs), was found to be, $F=ν$[17], and not that of the elementary charge, $F=e^*/e$[18,19]. These observations point to interference of bunched (clustered) elementary quasiparticles as coherent pairs, triples, and quadruplets, respectively. A small metallic gate (top gate, TG), deposited in the center of the interferometer bulk, forming an antidot (or a dot) when charged, thus introducing local quasiparticles at the (anti)dots perimeter. Surprisingly, such charging led to a dissociation of the bunched quasiparticles and thus recovered the conventional flux periodicity set by the elementary quasiparticles charge. However, the shot noise Fano factor (of each QPC) consistently remained at $F=ν$, possibly due to the neutral modes accompanied the conjugated states. The two observations - bunching and debunching (or dissociation) - are not expected by current theories. Similar effects may likely arise in Jains particle states (at lower temperatures) and at even denominator FQH states[20]

cond-mat.mes-hall↗

arXiv2024

Topological Thermal Hall Conductance of Even Denominator Fractional States

The even denominator fractional quantum Hall (FQH) states $ν=5/2$ and $ν=7/2$ have been long predicted to host non-abelian quasiparticles (QPs). Their present energy-carrying neutral modes are hidden from customary conductance measurements and thus motivate thermal transport measurements, which are sensitive to all energy-carrying modes. While past `two-terminal' thermal conductance ($k_{2t}T$) measurements already proved the non-Abelian nature of the $ν=5/2$ FQH state, they might have been prone to a lack of thermal equilibration among the counter-propagating edge modes. Here, we report a novel thermal Hall conductance measurement of the $ν=5/2$ and $ν=7/2$ states, being insensitive to equilibration among edge modes. We verify the state's non-Abelian nature, with both states supporting a single upstream Majorana edge mode (hence, a particle-hole Pfaffian order). While current numerical works predict a different topological order, this contribution should motivate further theoretical work.

cond-mat.mes-hall↗

arXiv2024

Scaling tunnelling noise in the fractional quantum Hall effect tells about renormalization and breakdown of chiral Luttinger liquid

The fractional quantum Hall (FQH) effect provides a paradigmatic example of a topological phase of matter. FQH edges are theoretically described via models belonging to the class of chiral Luttinger liquid (CLL) theories [1 (Wen, 2007)]. These theories predict exotic properties of the excitations, such as fractional charge and fractional statistics. Despite theoretical confidence in this description and qualitative experimental confirmations, quantitative experimental evidence for CLL behaviour is scarce. In this work, we study tunnelling between edge modes in the quantum Hall regime at the filling factor $ν=1/3$. We present measurements at different system temperatures and perform a novel scaling analysis of the experimental data, originally proposed in Ref. [2 (Schiller et al., 2022)]. Our analysis shows clear evidence of CLL breakdown - above a certain energy scale. In the low-energy regime, where the scaling behaviour holds, we extract the property called the scaling dimension and find it heavily renormalized compared to naïve CLL theory predictions. Our results show that decades-old experiments contain a lot of previously overlooked information that can be used to investigate the physics of quantum Hall edges. In particular, we open a road to quantitative experimental studies of (a) scaling dimension renormalization in quantum point contacts and (b) CLL breakdown mechanisms at an intermediate energy scale, much smaller than the bulk gap.

cond-mat.mes-hall↗

arXiv2023

Measuring statistics-induced entanglement entropy with a Hong-Ou-Mandel interferometer

Despite its ubiquity in quantum computation and quantum information, a universally applicable definition of quantum entanglement remains elusive. The challenge is further accentuated when entanglement is associated with other key themes, e.g., quantum interference and quantum statistics. Here, we introduce two novel motifs that characterize the interplay of entanglement and quantum statistics: an 'entanglement pointer' and a 'statistics-induced entanglement entropy'. The two provide a quantitative description of the statistics-induced entanglement: (i) they are finite only in the presence of quantum entanglement underlined by quantum statistics; (ii) their explicit form depends on the quantum statistics of the particles (e.g., fermions, bosons, anyons). We have experimentally implemented these ideas by employing an electronic Hong-Ou-Mandel interferometer fed by two highly diluted electron beams in an integer quantum Hall platform. Performing measurements of auto-correlation and cross-correlation of current fluctuations of the scattered beams (following 'collisions'), we quantify the statistics-induced entanglement by experimentally accessing the entanglement pointer and the statistics-induced entanglement entropy. Our theoretical and experimental approaches pave the way to study entanglement in various correlated platforms, e.g., those involving anyonic Abelian and non-Abelian states.

cond-mat.mes-hall↗

arXiv2023

Heat Conductance of the Quantum Hall Bulk

The Quantum Hall Effect (QHE) is a prototypical realization of a topological state of matter. It emerges from a subtle interplay between topology, interactions, and disorder. The disorder enables the formation of localized states in the bulk that stabilize the quantum Hall states with respect to the magnetic field and carrier density. Still, the details of the localized states and their contribution to transport remain beyond the reach of most experimental techniques. Here, we describe an extensive study of the bulk's heat conductance. Using a novel 'multi-terminal' short device (on a scale of $10 μm$), we separate the longitudinal thermal conductance, $κ_{xx}T$ (due to bulk's contribution), from the topological transverse value $κ_{xy}T$, by eliminating the contribution of the edge modes. When the magnetic field is tuned away from the conductance plateau center, the localized states in the bulk conduct heat efficiently ($κ_{xx}T \propto T$), while the bulk remains electrically insulating. Fractional states in the first excited Landau level, such as the $ν=7/3$ and $ν=5/2$, conduct heat throughout the plateau with a finite $κ_{xx} T$. We propose a theoretical model that identifies the localized states as the cause of the finite heat conductance, agreeing qualitatively with our experimental findings.

cond-mat.mes-hall↗

arXiv2023

Anomalous Aharonov-Bohm Interference in the Presence of Edge Reconstruction

Interferometry is a vital tool for studying fundamental features in the quantum Hall effect (QHE). For instance, Aharonov-Bohm (AB) interference in a quantum Hall interferometer can probe the wave-particle duality of electrons and quasiparticles. Here, we report an unusual AB interference in a quantum Hall Fabry-Pérot interferometer (FPI), whose Coulomb interactions were suppressed with a grounded drain in the interior bulk of the FPI. In a descending filling factor from $ν=3$ to $ν\approx5/3$, the magnetic field periodicity, which corresponded to a single 'flux quantum,' agreed accurately with the enclosed area of the FPI. However, in the filling range, $ν\approx5/3$ to $ν=1$, the field periodicity increased markedly, apriori suggesting a drastic shrinkage of the AB area. Moreover, the modulation gate voltage periodicity decreased abruptly at this range. We attribute these unexpected observations to a ubiquitous edge reconstruction, leading to dynamical area changing with the field and a modified modulation gate-edge capacitance. These results are reproducible and support future interference experiments with a QHE-FPI.

cond-mat.mes-hall↗

arXiv2023

Partitioning of Diluted Anyons Reveals their Braiding Statistics

Correlations of partitioned particles carry essential information about their quantumness. Partitioning full beams of charged particles leads to current fluctuations, with their autocorrelation (namely, shot noise) revealing the particle' charge. This is not the case when the partitioned particle beams are diluted. Bosons or fermions will exhibit particles antibunching (due to their sparsity and discreteness). However, when diluted anyons, such as the quasiparticles in fractional quantum Hall states, are partitioned in a narrow constriction, their autocorrelation reveals an essential aspect of their exchange statistics: their braiding phase. Here, we describe detailed measurements of weak partitioned, highly diluted, one-dimension-like edge modes of the one-third filling fractional quantum Hall state. The measured autocorrelation agrees with our theory of braiding anyons in the time-domain (instead of braiding in space); with a braiding phase 2$θ$=2$π$/3, without any fitting parameters. Our work offers a relatively straightforward and simple method to observe the braiding statistics of other exotic anyonic states, such as non-abelian states, without resorting to complex interference experiments.

cond-mat.mes-hall↗

arXiv2023

Electron Pairing of Interfering Interface-Based Edge Modes

The remarkable Cooper-like pairing phenomenon in the Aharonov-Bohm interference of a Fabry-Perot interferometer (FPI)$\rm{-}$operating in the integer quantum Hall regime$\rm{-}$remains baffling. Here, we report the interference of paired electrons employing 'interface edge modes'. These modes are born at the interface between the bulk of the FPI and an outer gated region tuned to a lower filling factor. Such configuration allows toggling the spin and the orbital of the Landau level (LL) of the edge modes at the interface. We find that electron pairing occurs only when the two modes (the interfering outer and the first inner) belong to the same spinless LL.

cond-mat.mes-hall↗

arXiv2022

Direct Determination of the Topological Thermal Conductance via Local Power Measurement

Thermal conductance measurements, sensitive to charge and chargeless energy flow, are evolving as an essential measurement technique in Condensed Matter Physics. For two-dimensional topological insulators, the measurements of the thermal Hall conductance, $κ_{xy}T$, and the longitudinal one $κ_{xx}T$, are crucial for the understanding of their underlying topological order. Such measurements are thus far lacking, even in the extensively studied quantum Hall effect (QHE) regime. Here, we report a new local power measurement technique that reveals the topological thermal Hall conductance (not the ubiquitous two-terminal one). For example, we find $κ_{xy}\sim0$ of the challenging $ν=2/3$ particle-hole conjugated state. This is in contrast to the two-terminal measurement, which provides a non-universal value that depends on the extent of thermal equilibration between the counter-propagating edge modes. Moreover, we use this technique to study the power carried by the current fluctuations in a partitioned edge mode with an out-of-equilibrium distribution.

cond-mat.mes-hall↗

arXiv2022

Anyonic interference and braiding phase in a Mach-Zehnder Interferometer

The fractional quantum Hall states have long been predicted to be a testing ground of fractional (anyonic) exchange statistics. These topological states harbor quasiparticles with fractional charges of both abelian and non-abelian characters. The quasiparticles' charge is commonly determined by shot noise measurements (1, 2), and states' statistics can be revealed by appropriately interfering the quasiparticles. While the multipath Fabry-Perot electronic interferometer (FPI) is easier to fabricate, it is often plagued by Coulomb interactions (3), its area breathes with the magnetic field (4), and its bulk's charges tend to fluctuate (5). Recent FPI experiments employing adequate screening allowed an observation of Aharonov-Bohm (AB) interference at bulk filling $ν$=1/3 (6). In the current work, we chose to employ an interaction-free, two-path, Mach-Zehnder interferometer (MZI), tuned to bulk filling $ν$=2/5. Interfering the outer $ν$=1/3 mode (with the inner $ν$=1/15 mode screening out the bulk), we observed a 'dressed AB' periodicity, with a combined 'bare AB' flux periodicity of three flux-quanta (3$ϕ_0$) and the 'braiding phase' 2$π$/3. This unique interference resulted with an AB periodicity of a single flux-quantum. Moreover, the visibility of the interference, $v_{e/3}$, deviated markedly from that of the electronic one $\it{v}_{e}$, agreeing with the theoretically expected visibility, $\it{v}_{e/3} \sim {\it{v}_e}^3$. With the two non-equivalent drains of the MZI, the fractional visibility peaked away from the ubiquitous transmission-half of the MZI. We provide simple theoretical arguments that support our results. The MZI proves to be a powerful tool that can be used to probe further the statistics of more complex anyonic quasiparticles.

cond-mat.mes-hall↗

arXiv2021

Isolated Ballistic Non-Abelian Interface Channel

Non-abelian anyons are prospective candidates for fault-tolerant topological quantum computation due to their long-range entanglement. Curiously these quasiparticles are charge-neutral, hence elusive to most conventional measurement techniques. A proposed host of such quasiparticles is the $ν$=5/2 quantum Hall state. The gapless edge modes can provide the topological order of the state, which in turn identifies the chirality of the non-abelian mode. Since the $ν$=5/2 state hosts a variety of edge modes (integer, fractional, neutral), a robust technique is needed to isolate the fractional channel while retaining its original non-abelian character. Moreover, a single non-abelian channel can be easily manipulated to interfere, thus revealing the state's immunity to decoherence. In this work, we exploit a novel approach to gap-out the integer modes of the $ν$=5/2 state by interfacing the state with integer states, $ν$=2 & $ν$=3 (1). The electrical conductance of the isolated interface channel was 0.5e$^2$/h, as expected. More importantly, we find a thermal conductance of 0.5$κ_0$T (with $κ_0$=$π^2k_B^2$/3h), confirming unambiguously the non-abelian nature of the $ν$=1/2 interface channel and its Particle-Hole Pfaffian topological order. Our result opens new avenues to manipulate and test other exotic QHE states and braid, via interference, the isolated fractional channels.

cond-mat.mes-hall↗

arXiv2021

Does shot noise always provide the quasiparticle charge?

The fractional charge of quasiparticles is a fundamental feature of quantum Hall effect (QHE) States. The charge has long been measured via shot-noise at moderate temperatures ($T$>30mK), with the Fano factor $F=e^*/e$ revealing the charge $e^*$ of the quasiparticles. However, at sufficiently low temperatures ($T\approx$10mK), we consistently find $F$ being equal to the bulk filling factor, $ν_b$. Surprisingly, noise with $F=ν_b$ is also observed on intermediate conductance plateaus in the transmission of the quantum point contact (QPC), where shot noise is not expected. We attribute the unexpected Fano factor to upstream neutral modes, which proliferate at the lowest spinless Landau level. The universality of the Fano factor is also confirmed when the edge modes do not conform to the bulk. For this, the ubiquitous edge modes at the periphery of the sample are replaced by artificially constructed 'interface modes', propagating at the interface between two adjoined QHE states: the tested state and a different state. We present a new theoretical paradigm based on an interplay between charge and neutral modes, explaining the origin of the universal Fano factor.

cond-mat.mes-hall↗