3D Yang-Mills glueballs vs closed effective strings

Recent lattice results strongly support the Axionic String Ansatz (ASA) for quantum numbers of glueballs in 3D Yang-Mills theory. The ASA treats glueballs as closed bosonic strings. The corresponding worldsheet theory is a deformation of the minimal Nambu-Goto theory. In order to understand better the ASA strings and as a first step towards a perturbative calculation of the glueball mass splittings we compare the ASA spectrum to the closed effective string theory. Namely, we model glueballs as excitations around the folded rotating rod solution with a large angular momentum J. The resulting spectrum agrees with the ASA in the regime of validity of the effective theory, i.e., in the vicinity of the leading Regge trajectory. In particular, closed effective string theory correctly predicts that only glueballs of even spin J show up at the leading Regge trajectory. Interestingly though, the closed effective string theory overestimates the number of glueball states far above the leading Regge trajectory.

Revisiting the flux tube spectrum of 3d SU(2) lattice gauge theory

We perform a high-precision measurement of the spectrum of the flux tube in three-dimensional $${\text {SU}}(2)$$ SU ( 2 ) gauge theory at multiple lattice spacings. We compare the results at large $$q\bar{q}$$ q q ¯ separations R to the spectrum predicted by the effective string theory, including the leading-order boundary term with a nonuniversal coefficient. We find qualitative agreement with the predictions from the leading-order Nambu–Goto string theory down to small values of R, while, at the same time, observing the predicted splitting of the second excited state due to the boundary term. On fine lattices and at large R, we observe slight deviations from the EST predictions for the first excited state.

Effective String Description of the Confining Flux Tube at Finite Temperature

In this review, after a general introduction to the effective string theory (EST) description of confinement in pure gauge theories, we discuss the behaviour of EST as the temperature is increased. We show that, as the deconfinement point is approached from below, several universal features of confining gauge theories, like the ratio Tc/σ0, the linear increase of the squared width of the flux tube with the interquark distance, or the temperature dependence of the interquark potential, can be accurately predicted by the effective string. Moreover, in the vicinity of the deconfinement point the EST behaviour turns out to be in good agreement with what was predicted by conformal invariance or by dimensional reduction, thus further supporting the validity of an EST approach to confinement.

Dark solitons, D-branes and noncommutative tachyon field theory

In this paper we discuss the boson/vortex duality by mapping the (3[Formula: see text]+[Formula: see text]1)D Gross–Pitaevskii theory into an effective string theory in the presence of boundaries. Via the effective string theory, we find the Seiberg–Witten map between the commutative and the noncommutative tachyon field theories, and consequently identify their soliton solutions with D-branes in the effective string theory. We perform various checks of the duality map and the identification of soliton solutions. This new insight between the Gross–Pitaevskii theory and the effective string theory explains the similarity of these two systems at quantitative level.

Effective string theory inspired potential and meson masses in higher dimension

Nambu–Goto action in classical bosonic string model for hadrons predicts quark-antiquark potential to be (Lüscher and Weisz. JHEP 07, 049 (2002). doi: 10.1088/1126-6708/2002/07/049 ) V(r) = −(γ/r) + σr + μ0. In this report we present studies of masses of heavy flavour mesons in higher dimension with our recently developed wave functions obtained following string inspired potential. We report the dimensional dependence of the masses of mesons. Our results suggest that as the meson mass increases with the number of extra spatial dimensions, it will attain the Planck scale (∼1019 GeV) asymptotically at an astronomically large spatial dimension (we call it Planck dimension) DPlanck ∼ 1011, which sets the limit of applicability of Schrodinger equation in large dimension.

Effective string description of confining flux tubes

We review the current knowledge about the theoretical foundations of the effective string theory for confining flux tubes and the comparison of the predictions to pure gauge lattice data. A concise presentation of the effective string theory is provided, incorporating recent developments. We summarize the predictions for the spectrum and the profile/width of the flux tube and their comparison to lattice data. The review closes with a short summary of open questions for future research.