The low-energy quasiparticle excitations in holeand electron-type cuprate superconductors are investigated via both experimental and theoretical means. It is found that the doping and momentum dependence of the empirical low-energy quasiparticle excitations is consistent with a scenario of coexisting competing orders and superconductivity in the ground state of the cuprates. This finding, based...

In a topological quantum computer, universal quantum computation is performed by dragging quasiparticle excitations of certain two dimensional systems around each other to form braids of their world lines in 2 + 1 dimensional space-time. In this Letter we show that any such quantum computation that can be done by braiding n identical quasiparticles can also be done by moving a single quasiparti...

We study the quasiparticle transport coefficients in disordered d-wave superconductors. We find that spin and charge excitations are generally localized unless magnetic impurities are present. If the system is close to a nesting point in the impurity-scattering unitary limit, the tendency towards localization is reduced while the quasiparticle density of states gets enhanced by disorder. We als...

Superconducting quasiparticle excitation spectra are computed for m times quantized flux lines using a self-consistent Bogoliubov–de Gennes approach. We find m discrete branches of bound-state solutions in the spectrum, corresponding to different values of the quasiparticle angular momentum. Owing to the bound states, the scanning tunneling microscopy spectrum of the vortex is predicted to disp...

In bulk Fermi liquids such as liquid He and nuclear matter the quasiparticle effective mass is enhanced at the Fermi surface and reduces to the bare mass far from the Fermi surface. We incorporate this central physical feature into the density and spin-density dynamics of normal-liquid He and obtain good agreement with recent high-resolution neutron-scattering experiments. Existing theories up ...

We argue based on theoretical considerations and analysis of experimental data that quasiparticle excitations near the nodes determine the low temperature properties in the superconducting state of cuprates. Quantum effects of phase fluctuations are shown to be quantitatively important, but thermal effects are small for T ≪ Tc. An anisotropic superfluid Fermi liquid phenomenology is presented f...

High-resolution photoemission has been used to study the electronic structure of the charge-density wave (CDW) and superconducting dichalcogenide, 2H-NbSe2. From the extracted self-energies, important components of the quasiparticle interactions have been identified. In contrast to previously studied TaSe2, the CDW transition does not affect the electronic properties significantly. The electron...

In Sn-I-Sn-I-Pb tunneling structures the energy gap ~Sn of Sn is reduced by quasiparticle injection via single-particle tunneling between the Sn films. ~Sn as function of the quasiparticle density is probed by the Pb contact and found in agreement with the theory of OWen and Scalapino. An instability of the energy gap of Sn is observed at the critical gap reduction ratio predicted by this theor...

Scanning tunneling spectroscopy was performed at 4.2 K on epitaxial thin-film heterostructures comprising YBa2Cu3O72d and La0.7Ca0.3MnO3, to study the microscopic effects of spin-polarized quasiparticle injection from the half-metallic ferromagnetic manganite on the high Tc cuprate superconductor. The quasiparticle tunneling characteristics observed were consistent with d-wave pairing symmetry,...

Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic fields to protect the integrity of the superconductivity. Here we show vortices can improve the performance of superconducting qubits by reducing th...