Chronological feed of everything captured from Sankar Das Sarma.
A light-front spectator model represents the proton as an active sea antiquark paired with a scalar-vector spectator, using soft-wall AdS/QCD spatial profiles. Parameters are fitted to CT18NNLO data and Bacchetta-Radici extractions at μ₀²=1.0 GeV², then evolved to μ²=100 GeV². The model predicts sustained \bar{d} enhancement at high x in agreement with E906 SeaQuest measurements and computes sea quark angular momentum via leading chiral-even GPDs.
Taylor, Das Sarma, and Musser construct a microscopic route to an electronic quantum charge liquid (QCL) — a translationally invariant, fractionalized state of fermions on a lattice — by pairing spinless fermions at filling ν=3/2 into bosons at ν=3/4 and studying a generalized tetramer model on the square lattice. Numerical analysis of tetramer wavefunctions reveals that at least one member of the family is gapped, and the model exhibits a local ℤ₄ symmetry. The authors propose this gapped, ℤ₄-symmetric state is a realization of the long-sought bosonic QCL with minimal ℤ₄ topological order. Extensions to other lattice geometries, fermionic QCLs, and Rydberg atom platforms are discussed.
SAGE qubits encode a logical qubit in four electrons across tunnel-coupled quantum dots using singlet-only, always-on gapless exchange, inherently protecting against magnetic-gradient-induced Pauli errors due to singlet invariance and continuous exchange. This design increases vulnerability to 1/f charge noise affecting chemical potentials and tunnel couplings, but CPMG-like sequences extend single-qubit coherence times under realistic noise. Two-qubit gate fidelities are improved via refocusing pulses and slower entangling ramps to suppress leakage.
In strong magnetic fields, increasing disorder in 2D electron systems induces transitions from classical Wigner crystals to local crystals and amorphous solids, with structure factors showing distinct peaks and rings in noninteracting cases. Fractional quantum Hall liquids similarly evolve from incompressible states to localized ordered solids and then amorphous solids as disorder strength rises. These phase transitions, driven by the interplay of disorder and interactions, align qualitatively with recent STM observations of homogeneous liquids turning into locally ordered then disordered solids.
A vision-transformer neural network can predict effective spin-orbit coupling (SOC) strength and generalized Hubbard model parameters from charge stability diagrams. By training on simulated data from 2x2 Ge hole quantum dot arrays with random disorder, the model achieves high predictive fidelity even when other system parameters are unknown.
This paper investigates magnon excitations in moiré Chern ferromagnets, focusing on their influence on magnetic stability and transition temperature at integer filling factor \nu = -1. The research reveals that magnon spectra exhibit isolated low-energy bands whose topological character is tunable via interlayer displacement. A key finding is that the magnon gap's sensitive dependence on the magnetic ground state's topology leads to an order-of-magnitude enhancement of the transition temperature (Tc) in the quantum anomalous Hall phase compared to topologically trivial correlated insulators.
This paper investigates the disordered interacting edge theory of fractional topological insulators at νtot=4/3, a system composed of two time-reversal-conjugated ν=2/3 fractional quantum Hall states. It identifies conditions under which interaction-induced insulating edge states can emerge without breaking fundamental symmetries, highlighting the limitations of two-terminal transport measurements for identifying these topological insulators.
A recent STM experiment observed three distinct quantum phases in 2D bilayer graphene under a strong magnetic field. This paper argues that one of these phases, a spatially random localized phase at low filling, is consistent with the proposed disorder-dominated strongly localized amorphous "Anderson solid" phase, presenting a generic occurrence at sample-dependent filling factors.
Recent experimental observations of a "solid" phase in 2D electron systems with quenched impurities are reinterpreted. This work argues that the observed phase is an Anderson solid, where impurities cause random spatial localization of charge carriers, rather than a Wigner solid formed by interaction-induced translational symmetry breaking. The key distinction lies in the role of disorder, leading to an amorphous solid adiabatically connected to an infinite disorder Anderson fixed point.