We investigate the transverse fluctuations of the confining string connecting two static quarks in $(2+1)\mathrm{D}$ $SU(2)$ Yang-Mills theory using Monte Carlo calculations. The exponentially suppressed signal is extracted from the large noise by a very efficient multilevel algorithm. The resulting width of the string increases logarithmically with the distance between the static quark charges. Corrections at intermediate distances due to universal higher-order terms in the effective string action are calculated analytically. They accurately fit the numerical data.

• Received 11 March 2010

DOI:https://doi.org/10.1103/PhysRevLett.104.232001