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Rasmus Normann Larsen

Publications and source records attributed to Rasmus Normann Larsen.

3 recordsLinked to original sources

Charmonium properties at high temperatures from lattice QCD

We study charmonium properties at non-zero temperature in the temperature range 153 MeV $<T<$ 305 MeV using lattice QCD. We use HISQ action for dynamical quarks and Wilson clover action for valence charm quarks and calculate the correlation function of extended meson operators. Our lattice QCD results are consistent with the existence of all charmonium states below the open charm threshold in this temperature region. However, charmonium states acquire sizable thermal width, which increases with increasing temperature. The size of the thermal width follows the hierarchy of charmonium sizes, i.e. the smaller ground state charmonium has a smaller thermal width than the larger excited charmonia.

hep-lat

Density of observables from local derivatives

We derive a formula to calculate the local change to the log of any density of states for smooth real observables. Using this in Monte-Carlo simulations, we are able to calculate the expectation value of the observable with a precision often better than standard sampling. The method can be applied to previously generated configurations, as long as the analysis uses the same action used to generate the configurations. We show that for observables such as Wilson line correlators, errors are reduced by up to 4 times.

hep-lat

Microscopic Spectral Density of the Wilson Dirac Operator for One Flavor

We consider the effect of a non-zero lattice spacing on the low-energy effective theory of Wilson fermions with one flavor. Analytical results are given for both the chiral condensate and the microscopic spectral density of the Wilson Dirac operator. A subtle mechanism ensures that a constant chiral condensate is recovered, once the sum over sectors of fixed index is performed.

hep-th