On fine structure of strings: the universal correction to the Veneziano amplitude

We study worldsheet theory of confining strings in two-dimensional massive adjoint QCD. Similarly to confining strings in higher dimensions this theory exhibits a nontrivial S-matrix surviving even in the strict planar limit. In the process of two-particle scattering a zigzag is formed on the worldsheet. It leads to an interesting non-locality and exhibits some properties of a quantum black hole. Ordinarily, identical quantum particles do not carry identity. On the worldsheet they acquire off-shell identity due to strings attached. Identity implies complementarity. We discuss similarities and differences of the worldsheet scattering with the TT deformation. We also propose a promising candidate for a supersymmetric model with integrable confining strings. IntroductionConstructng a theory of confining strings remains an interesting challenge. Large N gauge theories are closely related to gravity, with AdS/CFT [1-3] providing a concrete and spectacular example of this connection for conformal theories. The BFSS matrix model [4] and the matrix model for c = 1 strings [5] are other notable examples. Understanding the confining case is likely to give a further insight into gravitational dynamics.Recent progress in understanding of confining strings [6-9] is to large extent related to the identification of a new nice observable to focus on-the worldsheet S-matrix [10] (for other recent developments see, e.g., [11][12][13][14][15][16]). In the planar limit the worldsheet dynamics decouples from the bulk, and the worldsheet scattering is described by a UV complete unitary two-dimensional theory. There is a number of indications that this theory exhibits certain gravitational features rather than being just a conventional local quantum field theory. If this expectation is confirmed, it provides another concrete link between large N gauge theories and gravity.A somewhat surprising property of the worldsheet S-matrix is that it stays non-trivial even in the strict planar limit, N = ∞, when the bulk S-matrix turns free. This is an exact analogue of what happens in the critical string theory, where in the free limit, g s = 0, the worldsheet scattering remains non-trivial and describes an integrable model of twodimensional gravity [17].In three and four dimensions, D = 3, 4, a wealth of information about the worldsheet scattering can be extracted from lattice studies of confining flux tubes ( [18-24], see [25,26] for reviews). In the present paper we turn to the two-dimensional case, D = 2, where the analytical access to the worldsheet dynamics should be easier to achieve.The study of two-dimensional QCD has a long and fascinating history. In the pure Yang-Mills case neither the "bulk" 1 nor the worldsheet theory carry local degrees of freedom. The partition function and the Wilson loop corelators of this topological theory can be calculated exactly even at finite N [27-31]. The large N expansion of the exact answer can be explicitly recast in the form of perturbative string series [32][33][34].Introducing quarks in the fundam...

Section: Complementarity From Identitysupporting

confidence: 55%

“…Fig. 2) one naturally arrives at two different states corresponding to two color index contractions in (14) and (15), see Fig. 4.…”

Section: Distinguishable Particlesmentioning

confidence: 93%

Section: Distinguishable Particlesmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

A simple worldsheet black hole

Dubovsky

2018

“…Strings with electrically charged endpoint particles were analyzed in [14] and we currently investigate the role of the spin, which was considered also in [15,16]. In [17] it was shown that the the asymptotic behavior of the four point amplitude that corresponds to this model is a universal leading order correction of the Veneziano amplitude. Various other aspects of the model were investigated in [18][19][20][21][22][23][24][25].…”

Section: Contents 1 Introductionmentioning

confidence: 99%

Quantizing the rotating string with massive endpoints

Sonnenschein

Weissman

2018

We compute leading order quantum corrections to the Regge trajectory of a rotating string with massive endpoints using semiclassical methods. We expand the bosonic string action around a classical rotating solution to quadratic order in the fluctuations and perform the canonical quantization of the resulting theory. For a rotating string in D dimensions the intercept receives contributions from D − 3 transverse modes and one mode in the plane of rotation, in addition to a contribution due to the PolchinskiStrominger term of the non-critical effective string action when D = 26. The intercept at leading order is proportional to the expectation value of the worldsheet Hamiltonian of the fluctuations, and this is shown explicitly in several cases. All contributions to the intercept are considered, and we show a simple physical method to renormalize the divergences in them. The intercept converges to known results at the massless limit, and corrections from the masses are explicitly calculated at the long string limit. In the process we also determine the quantum spectrum of the string with massive endpoints, and analyze the asymmetric case of two different endpoint masses.

Closed strings and weak gravity from higher-spin causality

Kaplan

Kundu

2021

We combine old and new quantum field theoretic arguments to show that any theory of stable or metastable higher spin particles can be coupled to gravity only when the gravity sector has a stringy structure. Metastable higher spin particles, free or interacting, cannot couple to gravity while preserving causality unless there exist higher spin states in the gravitational sector much below the Planck scale Mpl. We obtain an upper bound on the mass Λgr of the lightest higher spin particle in the gravity sector in terms of quantities in the non-gravitational sector. We invoke the CKSZ uniqueness theorem to argue that any weakly coupled UV completion of such a theory must have a gravity sector containing infinite towers of asymptotically parallel, equispaced, and linear Regge trajectories. Consequently, gravitational four-point scattering amplitudes must coincide with the closed string four-point amplitude for s, t ≫ 1, identifying Λgr as the string scale. Our bound also implies that all metastable higher spin particles in 4d with masses m ≪ Λgr must satisfy a weak gravity condition.