Carlos Payá
@carlospaya.bsky.social
Predoc researcher at ICMM-CSIC.
Theory of Condensed Matter Physis.
Mc 7,31-37.
Theory of Condensed Matter Physis.
Mc 7,31-37.
Read the full paper on arxiv: arxiv.org/abs/2510.00921 9/9
Non-Hermitian Skin Effect and Electronic Nonlocal Transport
Open quantum systems governed by non-Hermitian effective Hamiltonians exhibit unique phenomena, such as the non-Hermitian skin effect, where eigenstates localize at system boundaries. We investigate t...
arxiv.org
October 2, 2025 at 9:15 AM
Read the full paper on arxiv: arxiv.org/abs/2510.00921 9/9
On a personal level, grateful to O. Solow and K. Flensberg @ucph.bsky.social for an inspiring 3-month sprint at QDev-NBI last spring. Bringing together our knowledge on non-Hermitian theory and quantum transport was a game-changer. Hope to collaborate more in the future! 8/9
October 2, 2025 at 9:15 AM
On a personal level, grateful to O. Solow and K. Flensberg @ucph.bsky.social for an inspiring 3-month sprint at QDev-NBI last spring. Bringing together our knowledge on non-Hermitian theory and quantum transport was a game-changer. Hope to collaborate more in the future! 8/9
Extra findings! Exceptional points—parameters where the Hamiltonian is not diagonalizable—shift between periodic and open boundaries. Our analysis reveals why these shifts occur in our Rashba-ferromagnet system. 7/9
October 2, 2025 at 9:15 AM
Extra findings! Exceptional points—parameters where the Hamiltonian is not diagonalizable—shift between periodic and open boundaries. Our analysis reveals why these shifts occur in our Rashba-ferromagnet system. 7/9
We prove the equivalence of these two pictures: directional spin dissipation ↔ non-Hermitian skin modes. Non-Hermitian physics offers a fresh lens to reinterpret familiar transport phenomena that hide under conventional Hermitian formalisms. 6/9
October 2, 2025 at 9:15 AM
We prove the equivalence of these two pictures: directional spin dissipation ↔ non-Hermitian skin modes. Non-Hermitian physics offers a fresh lens to reinterpret familiar transport phenomena that hide under conventional Hermitian formalisms. 6/9
Transport theory predicts a symmetric local conductance and a markedly non-reciprocal nonlocal conductance for large axial magnetic fields. We show that this non-reciprocity is a direct fingerprint of NHSE in electronic devices. 5/9
October 2, 2025 at 9:15 AM
Transport theory predicts a symmetric local conductance and a markedly non-reciprocal nonlocal conductance for large axial magnetic fields. We show that this non-reciprocity is a direct fingerprint of NHSE in electronic devices. 5/9
We consider Rashba wire coupled to a ferromagnetic lead. The lead induces spin-dependent dissipation, so one spin species decays faster. Via spin-momentum locking, this yields *directional dissipation*: right-movers attenuate strongly, left-movers hardly at all. 4/9
October 2, 2025 at 9:15 AM
We consider Rashba wire coupled to a ferromagnetic lead. The lead induces spin-dependent dissipation, so one spin species decays faster. Via spin-momentum locking, this yields *directional dissipation*: right-movers attenuate strongly, left-movers hardly at all. 4/9
In open quantum systems, effective non-Hermitian Hamiltonians can exhibit the NHSE, where eigenstates pile up at one boundary. Although demonstrated in photonics, its role in electronic transport remained elusive. What signatures should we see in a transport setup? 3/9
October 2, 2025 at 9:15 AM
In open quantum systems, effective non-Hermitian Hamiltonians can exhibit the NHSE, where eigenstates pile up at one boundary. Although demonstrated in photonics, its role in electronic transport remained elusive. What signatures should we see in a transport setup? 3/9
Main findings: In a Rashba nanowire + ferromagnetic lead, local conductance is symmetric, but nonlocal conductance
turns clearly non-reciprocal. This is a manifestation of directional dissipation mediated by spin, or, equivalently, the non-Hermitian skin effect (NHSE). 2/9
turns clearly non-reciprocal. This is a manifestation of directional dissipation mediated by spin, or, equivalently, the non-Hermitian skin effect (NHSE). 2/9
October 2, 2025 at 9:15 AM
Main findings: In a Rashba nanowire + ferromagnetic lead, local conductance is symmetric, but nonlocal conductance
turns clearly non-reciprocal. This is a manifestation of directional dissipation mediated by spin, or, equivalently, the non-Hermitian skin effect (NHSE). 2/9
turns clearly non-reciprocal. This is a manifestation of directional dissipation mediated by spin, or, equivalently, the non-Hermitian skin effect (NHSE). 2/9
Check also our quite related work on the Fluxoid Valve effect: t.co/B9i1LuyQS7
http://arxiv.org/abs/2504.16989
t.co
June 10, 2025 at 7:12 PM
Check also our quite related work on the Fluxoid Valve effect: t.co/B9i1LuyQS7
By correlating parameters of the system (e.g. nanowire radius, electrostatic profiles and junction transparency) with response in quantum transport, we provide a roadmap to engineer specific junction phases or even observe signatures of MZMs in full-shell hybrid nanowires.
June 10, 2025 at 7:12 PM
By correlating parameters of the system (e.g. nanowire radius, electrostatic profiles and junction transparency) with response in quantum transport, we provide a roadmap to engineer specific junction phases or even observe signatures of MZMs in full-shell hybrid nanowires.
Finally, we show that the competition between electron-like and hole-like CdGM analogs in the full-shell nanowires creates abrupt changes in the Josephson current direction, enabling 0-, π- and φ-junction behaviors.
June 10, 2025 at 7:12 PM
Finally, we show that the competition between electron-like and hole-like CdGM analogs in the full-shell nanowires creates abrupt changes in the Josephson current direction, enabling 0-, π- and φ-junction behaviors.
These peaks stand above the CdGM background, and could be used to demonstrate MZMs in these systems.
June 10, 2025 at 7:12 PM
These peaks stand above the CdGM background, and could be used to demonstrate MZMs in these systems.
For nanowire parameters in the topological regime, we show that Majorana zero modes (MZMs) —topological quasiparticles essential for fault-tolerant quantum computing— appear at the junction edges and produce “fin-shaped” peaks in the critical current at low transparency.
June 10, 2025 at 7:12 PM
For nanowire parameters in the topological regime, we show that Majorana zero modes (MZMs) —topological quasiparticles essential for fault-tolerant quantum computing— appear at the junction edges and produce “fin-shaped” peaks in the critical current at low transparency.
These critical current oscillations exhibit a characteristic skewness towards high fields within the lobes. The skewness is caused by Caroli-de Gennes-Matricon (CdGM) analogs, an exotic type of Andreev states recently predicted and observed experimentally in stand-alone wires.
June 10, 2025 at 7:12 PM
These critical current oscillations exhibit a characteristic skewness towards high fields within the lobes. The skewness is caused by Caroli-de Gennes-Matricon (CdGM) analogs, an exotic type of Andreev states recently predicted and observed experimentally in stand-alone wires.
In the presence of an axial magnetic field, we show that the critical current —the maximum supercurrent through the Josephson junction— is flux-modulated into different lobes as a consequence of Little-Parks (LP) effect of the shell.
June 10, 2025 at 7:11 PM
In the presence of an axial magnetic field, we show that the critical current —the maximum supercurrent through the Josephson junction— is flux-modulated into different lobes as a consequence of Little-Parks (LP) effect of the shell.
We identify key electrical signatures in junctions between full-shell nanowires —semiconductor cores fully encapsulated by a thin superconducting shell— linked to different quantum states possible in these nanostructures.
June 10, 2025 at 7:11 PM
We identify key electrical signatures in junctions between full-shell nanowires —semiconductor cores fully encapsulated by a thin superconducting shell— linked to different quantum states possible in these nanostructures.
Learn more about full-shell wires in our previous work:
- On symmetric Josephson junctions: arxiv.org/abs/2503.09756
- On full-shell wires theory: journals.aps.org/prb/abstract...
- An experiment demonstrating our theory on non-topological subgap states:
- On symmetric Josephson junctions: arxiv.org/abs/2503.09756
- On full-shell wires theory: journals.aps.org/prb/abstract...
- An experiment demonstrating our theory on non-topological subgap states:
Josephson effect and critical currents in trivial and topological full-shell hybrid nanowires
We perform microscopic numerical simulations of the Josephson effect through short junctions between two full-shell hybrid nanowires, comprised of a semiconductor core fully wrapped by a thin supercon...
arxiv.org
April 25, 2025 at 8:25 AM
Learn more about full-shell wires in our previous work:
- On symmetric Josephson junctions: arxiv.org/abs/2503.09756
- On full-shell wires theory: journals.aps.org/prb/abstract...
- An experiment demonstrating our theory on non-topological subgap states:
- On symmetric Josephson junctions: arxiv.org/abs/2503.09756
- On full-shell wires theory: journals.aps.org/prb/abstract...
- An experiment demonstrating our theory on non-topological subgap states:
The presence of Majorana zero modes at a tunnel junction significantly enhances the effect because their conductance depends on the square root of the transparency.
April 25, 2025 at 8:25 AM
The presence of Majorana zero modes at a tunnel junction significantly enhances the effect because their conductance depends on the square root of the transparency.
The effect is controlled by the applied magnetic field. It's perfect for cylindrically symmetric systems (red) and worsens as this symmetry is reduced (green and blue).
April 25, 2025 at 8:25 AM
The effect is controlled by the applied magnetic field. It's perfect for cylindrically symmetric systems (red) and worsens as this symmetry is reduced (green and blue).
When building a Josephson junction with full-shell nanowires with different radii, each wire can acquire a different superconducting phase winding. In this case, the supercurrent is blocked, while it's finite if they are equal.
April 25, 2025 at 8:25 AM
When building a Josephson junction with full-shell nanowires with different radii, each wire can acquire a different superconducting phase winding. In this case, the supercurrent is blocked, while it's finite if they are equal.