arxiv:1411.6918
An understanding of the possible ways in which interactions can produce fundamentally new emergent many-body states is a central problem of condensed matter physics. We ask if a Fermi sea can arise in a system of bosons subject to contact interaction.
PoS(LATTICE2014)302
We present our recent results for the tensor network (TN) approach to lattice gauge theories. TN methods provide an efficient approximation for quantum many-body states. We employ TN for one dimensional systems, Matrix Product States, to investigate the 1-flavour Schwinger model. In this study, we compute the chiral condensate at finite temperature.
Phys. Rev. B, 91, 045138 (2015)
We analyze the error of approximating Gibbs states of local quantum spin Hamiltonians on lattices with Projected Entangled Pair States (PEPS) as a function of the bond dimension (D), temperature (β−1), and system size (N). First, we introduce a compression method in which the bond dimension scales as D=eO(log2(N/ϵ)) if β<O(log(N)).
arXiv:1412.7123
We perform a systematic investigation on the hexagon-singlet solid (HSS) states, which are a class of spin liquid candidates for the spin-1 kagome antiferromagnet. With the Schwinger boson representation, we show that all HSS states have exponentially decaying correlations and can be interpreted as a (special) subset of the resonating Affleck-Kennedy-Lieb-Tasaki (AKLT) loop states.
Phys. Rev. B 89, 241106 (2014)
We construct a family of simple fermionic projected entangled pair states (fPEPS) on the square lattice with bond dimension D=3 which are exactly hole-doped resonating valence bond (RVB) wavefunctions with short-range singlet bonds. Under doping the insulating RVB spin liquid evolves immediately into a superconductor with mixed d+is pairing symmetry whose pair amplitude grows as the square-root of the doping.
arXiv:1410.4186
We numerically construct slowly relaxing local operators in a nonintegrable spin-1/2 chain. Restricting the support of the operator to M consecutive spins along the chain, we exhaustively search for the operator that minimizes the Frobenius norm of the commutator with the Hamiltonian and show that the Frobenius norm bounds the time scale of relaxation of the operator.
arXiv:1411.2995
It is commonly believed that area laws for entanglement entropies imply that a quantum many-body state can be faithfully represented by efficient tensor network states - a conjecture frequently stated in the context of numerical simulations and analytical considerations. In this work, we show that this is in general not the case, except in one dimension.
Phys. Rev. B 91, 115117
We analyze the strongly correlated regime of a two-component trapped ultracold fermionic gas in a synthetic non-Abelian U(2) gauge potential, that consists of both a magnetic field and a homogeneous spin-orbit coupling. This gauge potential deforms the Landau levels (LLs) with respect to the Abelian case and exchanges their ordering as a function of the spin-orbit coupling.
Phys. Rev. A 90, 042305 (2014)
We analyze some crucial questions regarding the practical feasibility of quantum simulation for lattice gauge models. Our analysis focuses on two different models suitable for the quantum simulation of the Schwinger Hamiltonian which we investigate numerically using Tensor Networks.
Phys. Rev. B 91, 115133 (2015)
In this work we numerically study critical phases in translation-invariant Z_N parafermion chains with both nearest- and next-nearest-neighbor hopping terms. The model can be mapped to a Z_N spin model with nearest-neighbor couplings via a generalized Jordan-Wigner transformation and translation invariance ensures that the spin model is always self-dual.