Approaching a topological phase transition in Majorana nanowires

Abstract

Recent experiments have produced mounting evidence of Majorana zero modes in nanowire-superconductor hybrids. Signatures of an expected topological phase transition accompanying the onset of these modes nevertheless remain elusive. We investigate a fundamental question concerning this issue: Do well-formed Majorana modes necessarily entail a sharp phase transition in these setups? Assuming reasonable parameters, we argue that finite-size effects can dramatically smooth this putative transition into a crossover, even in systems large enough to support well-localized Majorana modes. We propose overcoming such finite-size effects by examining the behavior of low-lying excited states through tunneling spectroscopy. In particular, the excited-state energies exhibit characteristic field and density dependence, and scaling with system size, that expose an approaching topological phase transition. We suggest several experiments for extracting the predicted behavior. As a useful byproduct, the protocols also allow one to measure the wire's spin-orbit coupling directly in its superconducting environment.

13 pages, 8 figures

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Cited by in corpus (46)

• Majorana bound states in a coupled quantum-dot hybrid-nanowire system
• Quantized Majorana conductance
• Milestones toward Majorana-based quantum computing
• From Andreev to Majorana bound states in hybrid superconductor-semiconductor nanowires
• Ballistic Majorana nanowire devices
• Nonlocality of Majorana Modes in Hybrid Nanowires
• Measuring Majorana non-locality and spin structure with a quantum dot
• Experimental Phase Diagram of a One-Dimensional Topological Superconductor
• Hybridization at superconductor-semiconductor interfaces
• Majorana nanowires for topological quantum computation
• Conductance of a proximitized nanowire in the Coulomb blockade regime
• Electric field tunable superconductor-semiconductor coupling in Majorana nanowires
• Quantifying wave-function overlaps in inhomogeneous Majorana nanowires
• Effective g-factor in Majorana Wires
• Zero-energy pinning from interactions in Majorana nanowires
• Magnetically-driven colossal supercurrent enhancement in InAs nanowire Josephson junctions
• Closing of the Induced Gap in a Hybrid Superconductor-Semiconductor Nanowire
• Distinguishing trivial and topological zero energy states in long nanowire junctions
• Dynamics of Majorana-based qubits operated with an array of tunable gates
• Decays of Majorana or Andreev oscillations induced by steplike spin-orbit coupling
• Dephasing and leakage dynamics of noisy Majorana-based qubits: Topological versus Andreev
• Majorana oscillations modulated by Fano interference and dregree of non-locality in a topological superconducting nanowire-quantum dot system
• Linear and non-linear transport across a finite Kitaev chain: an exact analytical study
• Nonlocal conductance spectroscopy of Andreev bound states in gate-defined InAs/Al nanowires
• Majorana/Andreev crossover and the fate of the topological phase transition in inhomogeneous nanowires
• Conductance spectroscopy on Majorana wires and the inverse proximity effect
• Disorder robustness and protection of Majorana bound states in ferromagnetic chains on conventional superconductors
• Majorana bound state localization and energy oscillations for magnetic impurity chains on conventional superconductors
• Majorana quasiparticles of inhomogeneous Rashba chain
• Majorana oscillations and parity crossings in semiconductor-nanowire-based transmon qubits
• Spectral response of Josephson junctions with low-energy quasiparticles
• Superconducting islands with semiconductor-nanowire-based topological Josephson junctions
• Readout of parafermionic states by transport measurements
• Non-Hermitian zero-energy pinning of Andreev and Majorana bound states in superconductor-semiconductor systems
• Topological superconductivity at finite temperatures in proximitized magnetic nanowires
• 1D Majorana Goldstinos and partial supersymmetry breaking in quantum wires
• Curvature of gap closing features and the extraction of Majorana nanowire parameters
• Non-Hermiticity stabilized Majorana zero modes in semiconductor-superconductor nanowires
• Dispersive 1D Majorana modes with emergent supersymmetry in 1D proximitized superconductors via spatially-modulated potentials and magnetic fields
• Quantum engineering of Majorana quasiparticles in one-dimensional optical lattices
• Concomitant opening of a topological bulk-gap with an emerging Majorana edge-state
• Majorana modes in striped two-dimensional inhomogeneous topological superconductors
• Topological transitions in two-dimensional Floquet superconductors
• Ising quantum criticality in Majorana nanowires
• Quantifying the non-Abelian property of Andreev bound states in inhomogeneous Majorana nanowires
• Majorana modes in helical altermagnet without net magnetism and spin-orbit coupling