nucl-th digest · Nov 12, 2018

Unwrapping phase fluctuations in one dimension

Correlation functions in one-dimensional complex scalar field theory provide a toy model for phase fluctuations, sign problems, and signal-to-noise problems in lattice field theory. Phase unwrapping techniques from signal processing are applied to lattice field theory in order to map compact random phases to noncompact random variables that can be numerically sampled without sign or signal-to-noise problems. A cumulant expansion can be used to reconstruct average correlation functions from moments of unwrapped phases, but points where the field magnitude fluctuates close to zero lead to ambiguities in the definition of the unwrapped phase and significant noise at higher orders in the cumulant expansion. Phase unwrapping algorithms that average fluctuations over physical length scales improve, but do not completely resolve, these issues in one dimension. Similar issues are seen in other applications of phase unwrapping, where they are found to be more tractable in higher dimensions.

↳ hep-latcond-mat.stat-mechhep-thnucl-th+1PoS(2018)·0 citations

Heavy-Quark Symmetry Partners of the Pc(4450) Pentaquark

Ming-Zhu Liu🇨🇳 · Fang-Zheng Peng🇨🇳 · Mario Sanchez Sanchez🇫🇷 · Manuel Pavon Valderrama🇨🇳

The spectrum of heavy-hadron molecules is constrained by heavy-quark symmetry in its different manifestations. Heavy-quark spin symmetry for instance connects the properties of the ground and excited states of heavy hadrons, while heavy-antiquark-diquark symmetry connects the properties of heavy antimesons ( $D ˉ$ , $D ˉ^{*}$ ) and doubly heavy baryons ( $Ξ_{cc}$ , $Ξ_{cc}^{*}$ ). A prediction of these symmetries is that if the $P_{c} (4450)$ is indeed a $D ˉ^{*} Σ_{c}$ bound state, then there should be a series of $D ˉ^{*} Σ_{c}^{*}$ , $Ξ_{cc} Σ_{c}$ , $Ξ_{cc}^{*} Σ_{c}$ , $Ξ_{cc} Σ_{c}^{*}$ and $Ξ_{cc}^{*} Σ_{c}^{*}$ partners. The concrete application of heavy-quark spin symmetry indicates that, if the $P_{c} (4450)$ is a $\frac{3}{2}^{-}$ $D ˉ^{*} Σ_{c}$ molecule, the existence of a $\frac{5}{2}^{-}$ $D ˉ^{*} Σ_{c}^{*}$ partner with similar binding energy --- which we call $P_{c} (4515)$ , given its expected mass --- is likely. Conversely, the application of heavy-antiquark-diquark symmetry indicates that the $0^{+}$ $Ξ_{cc} Σ_{c}$ , $1^{+}$ $Ξ_{cc} Σ_{c}^{*}$ , $2^{+}$ $Ξ_{cc}^{*} Σ_{c}$ and $3^{+}$ $Ξ_{cc}^{*} Σ_{c}^{*}$ molecules are likely to bind too, with binding energies in the $20 - 30 MeV$ range.

↳ hep-phhep-exhep-latnucl-thPRD(2018)·51 citations

Monday·November 12, 2018

Unwrapping phase fluctuations in one dimension

Heavy-Quark Symmetry Partners of the Pc(4450) Pentaquark

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