强关联电子
We study the effect of disorder on Z$_2$ quantum spin liquids with a Majorana Fermi line (respectively surface in three dimensions) and show that depending on the symmetries that are preserved \emph{on average} qualitatively different…
We present results of a Raman scattering study of the Kagome ferromagnet Co$_3$Sn$_2$S$_2$, with a focus on electronic and phononic excitations and their interplay. We provide a theoretical analysis of the electronic band structure,…
We propose trial wave functions for quasiparticle and exciton excitations of the Moore-Read Pfaffian fractional quantum Hall states, both for bosons and for fermions, and study these numerically. Our construction of trial wave functions…
The formation of excitonic insulator phases in quantum materials is often masked by structural distortions caused by the coupling between electronic and phononic order parameters. Here we show that the candidate material Ta$_2$NiSe$_5$ is…
We investigate the ground-state phase diagram of the $S$=1/2 XXZ model on the two-dimensional Shastry-Sutherland lattice using exact diagonalization (ED), density-matrix renormalization group (DMRG), and cluster mean-field theory (CMFT)…
Classical and quantum spin ice models are amongst the most popular settings for the study of spin liquid physics. $N-$state Potts ice models have been constructed that generalize spin ice, hosting multiple emergent $\text{U}(1)$ gauge…
We theoretically study the emergence of topological magnons in electron-magnon coupled systems. The magnon dispersion in a ferromagnet usually possesses an effective time reversal symmetry in the absence of Dzyaloshinskii-Moriya (DM)…
We theoretically investigate the physical properties of the magnetic van der Waals material GdGaI. Using first-principles calculations, we compute the phonon dispersion of GdGaI and show no imaginary phonons, suggesting that phonon-driven…
We investigate the Yb valence instabilities in the strongly correlated YbPd compound using resonant X-ray emission spectroscopy as a function of pressure across the charge-order (CO) transition. At a low temperature (T = 30 K) in the CO…
Non-trivial topological phases often emerge in narrow-gap semiconductors with a delicate blend of spin-orbit coupling and electron correlation. The diamond-lattice allotrope of Sn ($\alpha$-Sn) exemplifies this behavior, hosting multiple…
We study the instabilities to the conformal critical point of an exactly solvable family of Gross-Neveu models. Using conformal field theory techniques, we construct the zero-temperature phase diagram and identify the superconducting and…
Quantum phase transitions are among the most intriguing phenomena that can occur when the electronic ground state of correlated metals are tuned by external parameters such as pressure, magnetic field or chemical substitution. Such…
We study a two-orbital attractive Hubbard model with a repulsive Hund's exchange coupling $J$ as an idealized model for a two-band superconductor. This framework is motivated by a system where a large isotropic electron-phonon coupling…
We investigate a single magnetic impurity in the presence of strong spin-orbit coupling and single-ion anisotropy. We show that at sufficiently strong coupling there exists a finite temperature window, before the moment is completely…
Interaction quenches in strongly correlated electron systems provide a powerful route to probe nonequilibrium many-body dynamics. For the Hubbard model, nonequilibrium dynamical mean-field theory has revealed coherent post-quench…
We present a systematic comparison of the real-time Dyson expansion (RTDE) with established non-equilibrium Green's function approaches for simulating driven, interacting quantum systems. Focusing on density matrix dynamics,…
Recent works have suggested that transient suppression of a charge density wave (CDW) by an ultra-short excitation can lead to an inversion of the CDW phase. We experimentally investigate the dynamics of the CDW in K$_{0.3}$MoO$_{3}$ by…
We have studied the magnetic properties of clinoatacamite Cu$_2$Cl(OH)$_3$, the parent compound of the quantum spin liquid candidate herbertsmithite and a longstanding puzzle among frustrated quantum magnets. As we reveal using…
Geometrically frustrated triangular-lattice magnets provide fertile ground for realizing intriguing quantum phases such as spin supersolids. A common expectation is that spin-orbit coupling (SOC), which breaks continuous spin rotational…
The toric code, when deformed in a way that preserves the self-duality $\mathbb{Z}_2$ symmetry exchanging the electric and magnetic excitations, admits a transition to a topologically trivial state that spontaneously breaks the…