Nonequilibrium Spin Noise and Noise of Susceptibility

Abstract

We analyze out-of-equilibrium fluctuations in a driven spin system and relate them to the noise of spin susceptibility. In the spirit of the linear response theory we further relate the noise of susceptibility to a $4$-spin correlation function in equilibrium. We show that, in contrast to the second noise (noise of noise), the noise of susceptibility is a direct measure of non-Gaussian fluctuations in the system. We develop a general framework for calculating the noise of susceptibility using the Majorana representation of spin-1/2 operators. We illustrate our approach by a simple example of non-interacting spins coupled to a dissipative (Ohmic) bath.

10 pages, 4 figures

References in corpus (15)

• Decoherence of flux qubits due to 1/f flux noise
• Model for l/f Flux Noise in SQUIDs and Qubits
• 1/f Flux Noise in Josephson Phase Qubits
• Dephasing of a superconducting flux qubit
• Magnetism in SQUIDs at Millikelvin Temperatures
• Microscopic origin of low frequency flux noise in Josephson circuits
• Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise
• Probing Noise in Flux Qubits via Macroscopic Resonant Tunneling
• Nonequilibrium Transport through a Kondo Dot: Decoherence Effects
• Geometrical dependence of low frequency noise in superconducting flux qubits
• Spin-like susceptibility of metallic and insulating thin films at low temperature
• Spin-spin correlators in Majorana representation
• SU(2)-invariant spin liquids on the triangular lattice with spinful Majorana excitations
• Correlated flux noise and decoherence in two inductively coupled flux qubits
• Probing High Frequency Noise with Macroscopic Resonant Tunneling

Cited by in corpus (6)

• Dephasing-assisted Gain and Loss in Mesoscopic Quantum Systems
• Keldysh meets Lindblad: Correlated Gain and Loss in Higher-Order Perturbation Theory
• Far from equilibrium field theory for strongly coupled light and matter: dynamics of frustrated multi-mode cavity QED
• Bilinear Majorana representations for spin operators with spin magnitudes $S>1/2$
• Second spectrum of charge carrier density fluctuations in graphene due to trapping/detrapping processes
• Prethermalization of light and matter in cavity-coupled Rydberg arrays