title: Spectrum of a magnetized strong-leg quantum spin ladder.
abstract: Inelastic neutron scattering is used to measure the spin excitation spectrum of the Heisenberg S=1/2 ladder material (C7H10N)2CuBr4 in its entirety, both in the gapped spin liquid and the magnetic field-induced Tomonaga-Luttinger spin liquid regimes. A fundamental change of the spin dynamics is observed between these two regimes. Density matrix renormalization group calculations quantitatively reproduce and help understand the observed commensurate and incommensurate excitations. The results validate long-standing quantum field-theoretical predictions but also test the limits of that approach.
authors.affiliation: Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Schmidiger
authors.affiliation: Department of Medical Imaging and Information Sciences, Interventional Neuroradiology Unit, University Hospitals of Geneva, CH-1211 Geneva, Switzerland and Laboratory for Hydraulic Machines, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Bouillot
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom.
authors.forename: T
authors.initials: T
authors.lastname: Guidi
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Bewley
authors.affiliation: HISKP, Universität Bonn, Nussallee 14-16, D-53115 Bonn, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kollath
authors.affiliation: DPMC-MaNEP, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Giamarchi
authors.affiliation: Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Zheludev
mesh_terms: D000473:Alkanes / Q000737:chemistry; D001965:Bromides / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D060526:Magnetic Fields; D011789:Quantum Theory
chemical_list: D000473:Alkanes; D001965:Bromides; C408079:cupric bromide; D003300:Copper