Spin & Charge Currents Controlled Via Dissipative Processes

Researchers have demonstrated a method for generating both charge and spin currents using a minimal set of controls: just two jump operators. The work, available on arXiv.org as a preprint with a license, details how these nonreciprocal operators, coupling spin species to different directions of motion, can induce current within a two-dimensional quantum system. By tuning the degree of nonreciprocity within these operators, the team found they could modify the dominant transport mechanism from spin to charge. Crucially, this current generation proved robust even when subjected to dephasing noise, maintaining the necessary steady-state occupation for non-zero currents. Dissipative Engineering for Quantum State Control Researchers investigate the generation and control of both charge and spin currents via nonreciprocal dissipative mechanisms in a two-dimensional system of spinful fermionic atoms, manipulating it with nonreciprocal jump operators. These operators couple each spin species to a different spatial direction of motion; the researchers found that only two such operators are sufficient to generate both types of current. By tuning the degree of nonreciprocity of the jump operators, they modify the dominant transport mechanism from spin to charge. They also checked that this nonreciprocal current generation mechanism is robust to dephasing noise, as even in the presence of this additional dissipative process the steady-state occupation distributions for the quasiparticle modes of the Hamiltonian remains non-trivial, an essential requirement to obtain non-zero currents. The realm of possibility offered by dissipative engineering has significantly grown due to its connection to the field of quantum active matter. Taking inspiration from classical active matter, the design of nonreciprocal dissipative couplings breaking detailed balance has led to the emergence of quantum collective effects not seen in equilibrium situations. Current investigations into actively controlling quantum materials increasingly focus on non-equilibrium dynamics, demanding methods to induce these dynamics while preserving quantum coherence. Dissipative engineering is a powerful tool emerging in this field, successfully used to design systems with unusual steady-state properties. Researchers used the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation formalism to model these complex interactions. These operators, when applied in the “weak dissipative coupling regime,” allow control over both the direction and magnitude of the generated currents. The current generation mechanism proves remarkably robust; even in the presence of additional dissipation, the steady-state occupation distributions for the quasiparticle modes of the Hamiltonian remains non-trivial, a key requirement for sustaining non-zero currents. Catalin-Mihai Halati at the Max Planck Institute for the Physics of Complex Systems and Jean-Sébastien Bernier of the University of Northern British Columbia have investigated a method for simultaneously generating charge and spin currents within a quantum system. Their work is available on arXiv.org as a preprint with a license and centers on the precise application of just two jump operators, each nonreciprocally coupling a specific spin orientation to a distinct direction of movement. This minimal configuration proves sufficient to induce both current types.

The team used the Gorini-Kossakowski-Sudarshan-Lindblad master equation formalism and a time-dependent generalized Gibbs ensemble approach to model the system’s behavior in a “weak dissipative coupling regime”. Notably, the generated currents demonstrate resilience against external noise. Their investigation, available on arXiv.org, reveals that a specific combination of coherent and dissipative processes can generate both types of current. The research goes beyond simply inducing current; it establishes a pathway for modifying its nature, not just adjusting the magnitude, but changing how the current is carried, from spin to charge. The study identifies this control as occurring within “the weak dissipative coupling regime,” suggesting a balance where dissipation enhances rather than diminishes quantum effects. The robustness of this current generation mechanism to dephasing noise is notable. Recent advances are expanding the possibilities within quantum active matter, inspiring designs to maintain quantum coherence in systems previously thought unstable. Researchers used the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation formalism to explore how to stabilize persistent currents, circulating flows of charge, without relying on traditional methods like applied magnetic fields. This builds on earlier work demonstrating the ability to engineer topological states and tailor the dynamics of interacting many-body systems through carefully designed dissipation. A new study is available on arXiv. This approach differs from most previous attempts to generate charge currents, which typically involved coupling reservoirs to system boundaries; instead, this method utilizes uniform dissipative couplings within the material itself. The work offers a pathway toward harnessing quantum effects in non-equilibrium systems. Recent advances now permit local charge current measurements in both ultracold atoms confined in optical lattices and within superconducting circuits. 👉 More information🗞 Controlling charge and spin currents through nonreciprocal dissipative processes✍️ Catalin-Mihai Halati and Jean-Sébastien Bernier🧠 ArXiv: https://arxiv.org/abs/2607.15767 Stay currentSee today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals. Tags: