arXiv subjects

Sage Stanish

Publications and source records attributed to Sage Stanish.

3 recordsLinked to original sources

arXiv2026

Field line slippage rate signatures in nonlinear force-free field extrapolations

Magnetic reconnection plays a central role in solar flares and coronal mass ejections. Identifying where reconnection is physically active within coronal magnetic field models is a key part of magnetic field analysis. We investigate the field line slippage rate as a physics-weighted proxy for three-dimensional reconnection in nonlinear force-free field (NLFFF) extrapolations. The slippage rate measures the instantaneous deviation of magnetic field lines from ideal evolution, due to non-ideal terms in Ohm's law, providing a direct link between magnetic geometry and reconnection physics. For NLFFFs, we show that the resistivity-induced slippage rate is governed by cross-field gradients of the field-aligned twist, thus establishing a clear connection between current structure and reconnection signatures. We further examine its relationship to the squashing factor $Q$, used to identify quasi-separatrix layers (QSLs). By deriving a scaling estimate, we demonstrate that strong magnetic squashing amplifies slippage only insofar as it produces small transverse length scales; large values of $Q$ alone do not guarantee significant reconnection. We apply this framework to a sequence of NLFFF extrapolations of NOAA active region 11158 spanning the X2.2 flare of 15 February 2011. The slippage rate reveals enhanced reconnection signatures associated with distinct phases of the active region's evolution. In comparison with the squashing factor, we show that the field line slippage rate provides a physics-weighted complement to QSL analysis, distinguishing between regions that are geometrically favourable for reconnection and those where reconnection is physically significant.

astro-ph.SR↗

arXiv2024

On turbulent magnetic reconnection: fast and slow mean steady-states

We investigate a model of turbulent magnetic reconnection introduced by Higashimori, Yokoi and Hoshino (Phys. Rev. Lett. 110, 255001) and show that the classic two-dimensional, steady-state Sweet-Parker and Petschek reconnection solutions are supported. We present evidence that these are the only two steady-state reconnection solutions, and we determine the criterion for their selection. Sweet-Parker reconnection occurs when there is no growth in turbulent energy, whereas Petschek reconnection occurs when the current density in the reconnecting current sheet is able to surpass a critical value, allowing for the growth of turbulent energy that creates the diffusion region. Further, we show that the Petschek solutions are self-similar, depending on the value of the turbulent time scale, and produce a universal steady reconnection rate. The self-consistent development of Petschek reconnection through turbulence, within the model, is an example of fast and steady magnetic reconnection without an explicit need for the collisionless terms in an extended Ohm's law.

physics.plasm-ph↗

arXiv2023

Quantum Error Correction Scheme for Fully Correlated Noise

This paper investigates quantum error correction schemes for fully-correlated noise channels on an $n$-qubit system, where error operators take the form $W^{\otimes n}$, with $W$ being an arbitrary $2\times 2$ unitary operator. In previous literature, a recursive quantum error correction scheme can be used to protect $k$ qubits using $(k+1)$-qubit ancilla. We implement this scheme on 3-qubit and 5-qubit channels using the IBM quantum computers, where we uncover an error in the previous paper related to the decomposition of the encoding/decoding operator into elementary quantum gates. Here, we present a modified encoding/decoding operator that can be efficiently decomposed into (a) standard gates available in the \texttt{qiskit} library and (b) basic gates comprised of single-qubit gates and CNOT gates. Since IBM quantum computers perform relatively better with fewer basic gates, a more efficient decomposition gives more accurate results. Our experiments highlight the importance of an efficient decomposition for the encoding/decoding operators and demonstrate the effectiveness of our proposed schemes in correcting quantum errors. Furthermore, we explore a special type of channel with error operators of the form $σ_x^{\otimes n}, σ_y^{\otimes n}$ and $σ_z^{\otimes n}$, where $σ_x, σ_y, σ_z$ are the Pauli matrices. For these channels, we implement a hybrid quantum error correction scheme that protects both quantum and classical information using IBM's quantum computers. We conduct experiments for $n = 3, 4, 5$ and show significant improvements compared to recent work.

quant-ph↗