The quantum crystal of electrons, predicted more than 80 years ago by Eugene Wigner, remains one the most elusive states matter. In this study, we observed one-dimensional Wigner directly imaging its charge density in real space. To image, with minimal invasiveness, many-body electronic a carbon nanotube, used another nanotube as scanning-charge perturbation. images obtained few electrons confined dimension match theoretical predictions for strongly interacting crystals. nature emerges...

We propose a novel many-body framework combining the density matrix renormalization group (DMRG) with valence-space (VS) formulation of in-medium similarity group. This hybrid scheme admits for favorable computational scaling in large-space calculations compared to direct diagonalization. The capacity VS-DMRG approach is highlighted ab initio neutron-rich nickel isotopes based on chiral two- and three-nucleon interactions, allows us perform converged computations ground excited state...

We develop a hybrid semiclassical method to study the time evolution of one-dimensional quantum systems in and out equilibrium. Our handles internal degrees freedom completely mechanically by modified time-evolving block decimation while treating orbital quasiparticle motion classically. can follow dynamics up scales well beyond reach standard numerical methods observe crossover between preequilibrated locally phase equilibrated states. As an application, we investigate quench fluctuations...

Linear response theory plays a prominent role in various fields of physics and provides us with extensive information about the thermodynamics dynamics quantum classical systems. Here we develop general for linear non-Hermitian systems nonunitary derive modified Kubo formula generalized susceptibility an arbitrary (Hermitian non-Hermitian) system perturbation. We use this to evaluate dynamical non-Hermitian, one-dimensional Dirac model imaginary real masses, perturbed by time-dependent...

We generalize the spectral sum rule preserving density matrix numerical renormalization group (DM-NRG) method in such a way that it can make use of an arbitrary number not necessarily Abelian local symmetries present quantum impurity system. illustrate benefits using non-Abelian by example calculations for $T$ two-channel Kondo model presence magnetic field, which conventional NRG methods produce large errors and/or take long run-time.

We propose a scheme to realize the Kondo model with tunable anisotropy using alkaline-earth atoms in an optical lattice. The new feature of our setup is Floquet engineering interactions time-dependent Zeeman shifts, that can be realized either state-dependent Stark shifts or magnetic fields. properties resulting strongly depend on ferromagnetic interactions. In particular, easy-plane couplings give rise singlet formation even though microscopic are all ferromagnetic. discuss both equilibrium...

A Luttinger liquid (LL) describes low energy excitations of many interacting one dimensional systems, and exhibits universal response both in out equilibrium. We analyze its behavior the non-Hermitian realm after quantum quenching to a $\mathcal{PT}$-symmetric LL by focusing on fermionic single particle density matrix. For short times, we demonstrate emergence unique phenomena, characteristic that correlations propagate faster than conventional maximal speed, known as Lieb-Robinson bound....

We consider a PT-symmetric Fermi gas with an exceptional point, representing the critical point between and symmetry broken phases. The low energy spectrum remains linear in momentum is identical to that of Hermitian gas. fermionic Green's function decays power law fashion for large distances, as expected from gapless excitations, although exponent reduced -1 due quantum Zeno effect. In spite nature ground state entanglement entropy saturates finite value, independent subsystem size...

The current emission noise of a carbon nanotube quantum dot in the Kondo regime is measured at frequencies ν order or higher than frequency associated with effect k(B)T (K)/h, TK temperature. coupled via an on-chip resonant circuit to detector, superconductor-insulator-superconductor junction. We find for hν ≈ k(B)T(K) related singularity voltage bias eV hν, and strong reduction this 3k(B)T(K), good agreement theory. Our experiment constitutes new original tool investigation nonequilibrium...

We generalize Nozi\`eres' Fermi-liquid theory for the low-energy behavior of Kondo model to that single-impurity Anderson model. In addition electrons' phase shift at Fermi energy, is characterized by four parameters: two given Nozi\`eres enter first order in excitation and additional ones second are needed away from particle-hole symmetry. express all parameters terms zero-temperature physical observables, namely local charge spin susceptibilities their derivatives with respect level...

We analyze the phase diagram associated with a pair of magnetic impurities trapped in superconducting host. The natural interplay between Kondo screening, superconductivity and exchange interactions leads to rich array competing phases, whose transitions are characterized by discontinuous changes total spin. Our analysis is based on combination numerical renormalization group techniques as well semi-classical analytics. In addition expected screened unscreened we observe new molecular...

Magnetic impurities embedded in a metal are screened by the Kondo effect, signaled formation of an extended correlation cloud, so-called or screening cloud. In superconductor, state turns into subgap Yu-Shiba-Rusinov states, and quantum phase transition occurs between unscreened phases once superconducting energy gap Δ exceeds sufficiently temperature, T_{K}. Here we show that, although does not form phase, cloud exist both phases. However, while is complete it only partial phase....

We investigate numerically the joint distribution of magic ($M$) and entanglement ($S$) in $N$-qubit Haar-random quantum states. The $P_N(M,S)$ as well marginals become exponentially localized, centered around values $\tilde{M_2} \to N-2$ $\tilde{S} N/2$ $N\to\infty$. Magic fluctuations are, however, found to uncorrelated. Although many states with $M_2=0$ entropy $S\approx S_\text{Haar}$ exist, they represent an small fraction compared typical states, which are characterized by large...

This paper is a corrected version of Phys. Rev. B 95, 165404 (2017), which we have retracted because it contained trivial but fatal sign error that lead to incorrect conclusions. We extend recently developed Fermi liquid (FL) theory for the asymmetric single-impurity Anderson model [C. Mora et al., 92, 075120 (2015)] case an arbitrary local magnetic field. To describe system's low-lying quasiparticle excitations values bare Hamiltonian's parameters, construct effective low-energy FL...

Abstract Various promising qubit concepts have been put forward recently based on engineered superconductor subgap states like Andreev bound states, Majorana zero modes or the Yu-Shiba-Rusinov (Shiba) states. The coupling of these via a strongly depends their spatial extension and is an essential next step for future quantum technologies. Here we investigate Shiba state in semiconductor dot coupled to superconductor. With detailed transport measurements numerical renormalization group...

We study non-hermitian many-body physics in the interacting Hatano-Nelson model with open boundary condition. The violation of reciprocity, resulting from an imaginary vector potential, induces skin-effect and causes exponential localization for all single particle eigenfunctions non-interacting limit. Nevertheless, density profile system becomes only slightly tilted relative to average filling. Friedel oscillations exhibit a beating pattern due modification Fermi wavenumber. probability...

We construct a real time current-conserving functional renormalization group (RG) scheme on the Keldysh contour to study frequency-dependent transport and noise through quantum dot in local moment regime. find that current vertex develops nontrivial nonlocal structure is governed by new set of RG equations. Solving these equations, we compute complete frequency temperature dependence spectrum. For voltages are large compared Kondo (i.e., $\mathit{eV}\ensuremath{\gg}{k}_{B}{T}_{K}$), two...

We investigate the spin-resolved transport properties, such as linear conductance and tunnel magnetoresistance, of a double quantum dot device attached to ferromagnetic leads look for signatures SU(4) symmetry in Kondo regime. show that behavior greatly depends on magnetic configuration device, spin-SU(2) well orbital spin-SU(4) effects become generally suppressed when varies from antiparallel parallel one. Furthermore, finite spin polarization lifts degeneracy drives system an orbital-SU(2)...

We use a semiclassical approach to study out of equilibrium dynamics and transport in quantum systems with massive quasiparticle excitations having internal numbers. In the universal limit low energy quasiparticles, system is described terms classical gas colored hard-core particles. Starting from an inhomogeneous initial state, this we give analytic expressions for space time dependent spin density current profiles. Depending on found be ballistic or diffusive. case identify `second front'...

We study a one-dimensional Fermi gas in the presence of dissipative coupling to environment through Lindblad equation. The dissipation involves energy exchange with and favours relaxation electrons excitations. After switching on dissipation, system approaches steady state, which is described by generalized Gibbs ensemble. fermionic single particle density matrix resembles deceivingly that hermitian interaction quench. It decays inversely distance for short times due correlations initial...

We study the effect of magnetic Mn ions on two-band superconductor ${\text{MgB}}_{2}$, and compute both total spin-resolved scanning tunneling spectrum in vicinity impurity. show that when internal structure ion's $d$-shell is taken into account, multiple Shiba states appear spectrum. The presence these multiplets could alter significantly overall interpretation local spectra for a wide range superconducting hosts impurities.

Quantum impurity models describe interactions between some local degrees of freedom and a continuum non-interacting fermionic or bosonic states. The investigation quantum is starting point towards the understanding more complex strongly correlated systems, but also provide description various mesoscopic structures, biological chemical processes, atomic physics phenomena such as dissipation dephasing. Prototypes these are Anderson model, single- multi-channel Kondo models. numerical...