5 papers
Exact strong zero modes are generic in integrable spin systems with large anisotropy
Sascha Gehrmann
Strong zero modes (SZMs) are edge-localized operators that commute with the Hamiltonian up to corrections exponentially small in system size, yielding anomalously long edge coheren…
Exact Quantum Many-Body Scars by a generalized Matrix-Product Ansatz
Sascha Gehrmann, Fabian H. L. Essler
We construct exact eigenstates of quantum many-body systems with Hamiltonians that are not frustration-free in matrix product form, based on a local error cancellation ansatz motiv…
Exact strong zero modes in quantum circuits and spin chains with non-diagonal boundary conditions
Sascha Gehrmann, Fabian H. L. Essler
We construct exact strong zero mode operators (ESZM) in integrable quantum circuits and the spin-1/2 XXZ chain for general open boundary conditions, which break the bulk U(1) symme…
XYZ integrability the easy way
Paul Fendley, Sascha Gehrmann, Eric Vernier +1
Sutherland showed that the XYZ quantum spin-chain Hamiltonian commutes with the eight-vertex model transfer matrix, so that Baxter's subsequent tour de force proves the integrabili…
Quantum-group-invariant models: Bethe ansatz and finite-size spectrum
Holger Frahm, Sascha Gehrmann, Rafael I. Nepomechie +1
We consider the quantum integrable spin chain models associated with the Jimbo R-matrix based on the quantum affine algebra , subject to quantum-group-invariant boun…