Excitations which carry "fractional" quantum numbers are known to exist in one dimension in polyacetylene, and in two dimensions, in the fractional quantum Hall effect. Fractional excitations have also been invoked to explain the breakdown of the conventional theory of metals in a wide range of three-dimensional materials. However, the existence of fractional excitations in three dimensions remains highly controversial. In this Letter we report direct numerical evidence for the existence of an extended quantum liquid phase supporting fractional excitations in a concrete, three-dimensional microscopic model-the quantum dimer model on a diamond lattice. We demonstrate explicitly that the energy cost of separating fractional monomer excitations vanishes in this liquid phase, and that its energy spectrum matches that of the Coulomb phase in (3+1)-dimensional quantum electrodynamics.Excitations which carry "fractional" quantum numbers are known to exist in one dimension in polyacetylene, and in two dimensions, in the fractional quantum Hall effect. Fractional excitations have also been invoked to explain the breakdown of the conventional theory of metals in a wide range of three-dimensional materials. However, the existence of fractional excitations in three dimensions remains highly controversial. In this Letter we report direct numerical evidence for the existence of an extended quantum liquid phase supporting fractional excitations in a concrete, three-dimensional microscopic model-the quantum dimer model on a diamond lattice. We demonstrate explicitly that the energy cost of separating fractional monomer excitations vanishes in this liquid phase, and that its energy spectrum matches that of the Coulomb phase in (3+1)-dimensional quantum electrodynamics.

arXiv:0901.1057Physical Review LettersDec 7, 200936 citations

Quantum Liquids: Excitations and Thermodynamic Properties

Kostya Trachenko

Cambridge University Press eBooksAug 17, 20230 citations

Extended quantum U(1) -liquid phase in a three-dimensional quantum dimer model

Olga Sikora, Nic Shannon, Frank Pollmann +2 more

Recently, quantum dimer models have attracted a great deal of interest as a paradigm for the study of exotic quantum phases. Much of this excitement has centered on the claim that a certain class of quantum dimer model can support a quantum $U(1)$ -liquid phase with deconfined fractional excitations in three dimensions. These fractional monomer excitations are quantum analogs of the magnetic monopoles found in spin ice. In this paper, we use extensive quantum Monte Carlo simulations to establish the ground-state phase diagram of the quantum dimer model on the three-dimensional diamond lattice as a function of the ratio $\ensuremath{\mu}$ of the potential to kinetic-energy terms in the Hamiltonian. We find that, for ${\ensuremath{\mu}}_{c}=0.75\ifmmode\pm\else\textpm\fi{}0.02$, the model undergoes a first-order quantum phase transition from an ordered `` $\mathsf{R}$ state'' into an extended quantum $U(1)$ -liquid phase, which terminates in a quantum critical Rokhsar-Kivelson (RK) point for $\ensuremath{\mu}=1$. This confirms the published field-theoretical scenario. We present detailed evidence for the existence of the $U(1)$ -liquid phase and indirect evidence for the existence of its photon and monopole excitations. Simulations are benchmarked against a variety of exact and perturbative results, and a comparison is made of different variational wave functions. We also explore the ergodicity of the quantum dimer model on a diamond lattice within a given flux sector, identifying a new conserved quantity related to transition graphs of dimer configurations. These results complete and extend the previous analysis of O. Sikora et al. [Phys. Rev. Lett. 103, 247001 (2009)].Recently, quantum dimer models have attracted a great deal of interest as a paradigm for the study of exotic quantum phases. Much of this excitement has centered on the claim that a certain class of quantum dimer model can support a quantum $U(1)$-liquid phase with deconfined fractional excitations in three dimensions. These fractional monomer excitations are quantum analogs of the magnetic monopoles found in spin ice. In this paper, we use extensive quantum Monte Carlo simulations to establish the ground-state phase diagram of the quantum dimer model on the three-dimensional diamond lattice as a function of the ratio $\ensuremath{\mu}$ of the potential to kinetic-energy terms in the Hamiltonian. We find that, for ${\ensuremath{\mu}}_{c}=0.75\ifmmode\pm\else\textpm\fi{}0.02$, the model undergoes a first-order quantum phase transition from an ordered ``$\mathsf{R}$ state'' into an extended quantum $U(1)$-liquid phase, which terminates in a quantum critical Rokhsar-Kivelson (RK) point for $\ensuremath{\mu}=1$. This confirms the published field-theoretical scenario. We present detailed evidence for the existence of the $U(1)$-liquid phase and indirect evidence for the existence of its photon and monopole excitations. Simulations are benchmarked against a variety of exact and perturbative results, and a comparison is made of different variational wave functions. We also explore the ergodicity of the quantum dimer model on a diamond lattice within a given flux sector, identifying a new conserved quantity related to transition graphs of dimer configurations. These results complete and extend the previous analysis of O. Sikora et al. [Phys. Rev. Lett. 103, 247001 (2009)].

arXiv:1105.1322Physical Review BSep 21, 201153 citations

Excitations in Two-Dimensional and Three-Dimensional Quantum Fluids

A. F. G. Wyatt, H. J. Lauter

NATO ASI series. Series B : PhysicsJan 1, 1991237 citations

Dynamical signatures of the one-dimensional deconfined quantum critical point

Ning Xi, Rong Yu

We study the critical scaling and dynamical signatures of fractionalized excitations at two different deconfined quantum critical points (DQCPs) in an S = 1/2 spin chain using the time evolution of infinite matrix product states. The scaling of the correlation functions and the dispersion of the conserved current correlations explicitly show the emergence of enhanced continuous symmetries at these DQCPs. The dynamical structure factors in several different channels reveal the development of deconfined fractionalized excitations at the DQCPs. Furthermore, we find an effective spin–charge separation at the DQCP between the ferromagnetic (FM) and valence bond solid (VBS) phases, and identify two continua associated with different types of fractionalized excitations at the DQCP between the X -direction and Z -direction FM phases. Our findings not only provide direct evidence for the DQCP in one dimension but also shed light on exploring the DQCP in higher dimensions.We study the critical scaling and dynamical signatures of fractionalized excitations at two different deconfined quantum critical points (DQCPs) in an S = 1/2 spin chain using the time evolution of infinite matrix product states. The scaling of the correlation functions and the dispersion of the conserved current correlations explicitly show the emergence of enhanced continuous symmetries at these DQCPs. The dynamical structure factors in several different channels reveal the development of deconfined fractionalized excitations at the DQCPs. Furthermore, we find an effective spin–charge separation at the DQCP between the ferromagnetic (FM) and valence bond solid (VBS) phases, and identify two continua associated with different types of fractionalized excitations at the DQCP between the X -direction and Z -direction FM phases. Our findings not only provide direct evidence for the DQCP in one dimension but also shed light on exploring the DQCP in higher dimensions.

arXiv:2202.13375Chinese Physics BMar 2, 20228 citations

U(1)

-liquid phase with deconfined fractional excitations in three dimensions. These fractional monomer excitations are quantum analogs of the magnetic monopoles found in spin ice. In this paper, we use extensive quantum Monte Carlo simulations to establish the ground-state phase diagram of the quantum dimer model on the three-dimensional diamond lattice as a function of the ratio $\ensuremath{\mu}$ of the potential to kinetic-energy terms in the Hamiltonian. We find that, for ${\ensuremath{\mu}}_{c}=0.75\ifmmode\pm\else\textpm\fi{}0.02$, the model undergoes a first-order quantum phase transition from an ordered ``

\mathsf{R}

state'' into an extended quantum

U(1)

-liquid phase, which terminates in a quantum critical Rokhsar-Kivelson (RK) point for $\ensuremath{\mu}=1$. This confirms the published field-theoretical scenario. We present detailed evidence for the existence of the

U(1)

-liquid phase and indirect evidence for the existence of its photon and monopole excitations. Simulations are benchmarked against a variety of exact and perturbative results, and a comparison is made of different variational wave functions. We also explore the ergodicity of the quantum dimer model on a diamond lattice within a given flux sector, identifying a new conserved quantity related to transition graphs of dimer configurations. These results complete and extend the previous analysis of O. Sikora et al. [Phys. Rev. Lett. 103, 247001 (2009)].