Relativistic String Research Articles

Born-Oppenheimer potentials for SU(3) gauge theory

We develop parametrizations of eight of the lowest Born-Oppenheimer potentials for quarkonium hybrid mesons as functions of the separation r of the static quark and antiquark sources. The parameters are determined by fitting results calculated using pure SU(3) lattice gauge theory. The parametrizations have the correct limiting behavior at small r, where the potentials form multiplets associated with gluelumps. They have the correct limiting behavior at large r, where the potentials form multiplets associated with excitations of a relativistic string. There is a narrow avoided crossing in the small-r region between two potentials with the same Born-Oppenheimer quantum numbers. Published by the American Physical Society 2024

Non-relativistic expansion of open strings and D-branes

We expand the relativistic open bosonic string in powers of 1/c2 where c is the speed of light. We perform this expansion to next-to-leading order in 1/c2 and relate our results to known descriptions of non-relativistic open strings obtained by taking limits. Just as for closed strings the non-relativistic expansion is well-defined if the open string winds a circle in the target space. This direction must satisfy Dirichlet boundary conditions. It is shown that the endpoints of the open string behave as Bargmann particles in the non-relativistic regime. These open strings end on nrDp-branes with p ≤ 24. When these nrDp-branes do not fluctuate they correspond to (p + 1)-dimensional Newton-Cartan submanifolds of the target space. When we include fluctuations and worldvolume gauge fields their dynamics is described by a non-relativistic version of the DBI action whose form we derive from symmetry considerations. The worldvolume gauge field and scalar field of a nrD24-brane make up the field content of Galilean electrodynamics (GED), and the effective theory on the nrD24-brane is precisely a non-linear version of GED. We generalise these results to actions for any nrDp-brane by demanding that they have the same target space gauge symmetries that the non-relativistic open and closed string actions have. Finally, we show that the nrDp-brane action is transverse T-duality covariant. Our results agree with the findings of Gomis, Yan and Yu in [1].

Nonequivalence of Carroll limits in relativistic string theory

We construct new Carroll strings in flat space by considering the Carroll limit of equivalent relativistic string theories at the classical level. In the limit these Carroll strings are no longer equivalent and have different degrees of freedom. This fact is due to a general phenomenon that the configuration space and canonical Lagrangians are no longer equivalent after a singular redefinition of the variables and of the parameters of the starting Lagrangians. Published by the American Physical Society 2024

Global stability of the plane wave solutions to the relativistic string equation with non-small perturbations

Global stability of the plane wave solutions to the relativistic string equation with non-small perturbations

On the Importance of Consideration of Initially-Extended Relativistic Strings for Hadronization Modeling

On the Importance of Consideration of Initially-Extended Relativistic Strings for Hadronization Modeling

Flowing from relativistic to nonrelativistic string vacua in AdS5×S5

We find the connection between relativistic and nonrelativistic string vacua in AdS5×S5 in terms of a free parameter c flow. First, we show that the famous relativistic BMN vacuum flows in the large c parameter to an unphysical solution of the nonrelativistic theory. Then, we consider the simplest nonrelativistic vacuum, found in Fontanella and García [] (called BMN-like), and we identify its relativistic origin, namely a noncompact version of the folded string with zero spin, ignored in the past due to its infinite energy. We show that, once the critical closed B-field required by the nonrelativistic limit is included, the total energy of such relativistic solution is finite, and in the large c parameter it precisely matches the one of the BMN-like string. We also analyze the case with spin in the transverse anti–de Sitter directions. Published by the American Physical Society 2024

Solitonic effect on relativistic string cloud spacetime attached with strange quark matter

<abstract><p>In this research paper, we discussed some geometric axioms of a relativistic string cloud spacetime attached with strange quark matter. We determined the conformal $ \eta $-Ricci soliton on a relativistic string cloud spacetime attached with strange quark matter with a $ \varphi(\mathcal{R}ic) $-vector field. In addition, we illustrated some physical significance of conformal pressure $ P $ in terms of conformal $ \eta $-Ricci soliton with the same vector field. Besides this, we deduced a generalized Liouville equation from the conformal $ \eta $-Ricci soliton. Furthermore, we examine the harmonic relevance of conformal $ \eta $-Ricci soliton on string cloud spacetime attached with strange quark matter with a potential function $ \psi $. Finally, we turned up a necessary and sufficient condition for the 1-form $ \eta $, which is the $ {g} $-dual of the vector field $ \gamma $ on a string cloud spacetime attached with strange quark matter to be a solution for the Schrödinger-Ricci equation.</p></abstract>

A Bare and Gravitationally Dressed Electron Formed from Kerr–Newman Black Hole

The Kerr–Newman (KN) electron model, based on the classical KN black hole solution, is modified by adding a “mirror” sheet of KN metric corresponding to a positron, that creates a heavy electron-positron vacuum core dressed by gravity, and allows us to consider the bare and dressed electron separately. The bare electron is formed as a massless relativistic ring string and is responsible for the wave properties of the electron, while the heavy supersymmetric vacuum core receives the additional mass-energy from two Wilson loops dragged by the KN gravitational field, thus creating a magnetically coupled monopole-antimonopole pair. As a result, the KN electron becomes consistent with wave nature of quantum electron and its gravitational interaction increases dramatically from Planck to Compton scale.

A Globally Smooth Solution to the Relativistic String Equation

A Globally Smooth Solution to the Relativistic String Equation

Non-relativistic string monodromies

Spectral curve methods proved to be powerful techniques in the context of relativistic integrable string theories, since they allow us to derive the semiclassical spectrum from the minimal knowledge of a Lax pair and a classical string solution. In this paper we initiate the study of the spectral curve for non-relativistic strings in AdS5 × S5. First, we show that for string solutions whose Lax connection is independent of σ, the eigenvalues of the monodromy matrix do not have any spectral parameter dependence. We remark that this particular behaviour also appears for relativistic strings in flat space. Second, for some simple non-relativistic string solutions where the path ordered exponential of the Lax connection can be computed, we show that the monodromy matrix is either diagonalisable with quasi-momenta independent of the spectral parameter, or non-diagonalisable. For the latter case, we propose a notion of generalised quasi-momenta, based on maximal abelian subalgebras, which retain a dependence on the spectral parameter.

Geometrization of string cloud spacetime in general relativity

<abstract><p>The purpose of the article is to analyze the behavior of spacetime using a string cloud energy-momentum tensor $ \mathcal{T} $ having string cloud fluid density $ \rho $ and string tension $ \lambda $, named <italic>relativistic string cloud spacetime</italic>. We obtain some results for string cloud spacetime with a divergence-free matter tensor and a diminishing space matter tensor. Next, we discuss some curvature characteristics, such as conformally flat, Ricci semi-symmetric and pseudo-Ricci-symmetric, for relativistic string cloud spacetime. In addition, we gain a condition that coincides with the equation of state for the cloud of geometric strings in Ricci semi-symmetric string cloud spacetime.</p></abstract>

The two-channel exotic charmonium-like resonances in the mass region (3900–4700) MeV

Numerous resonances in the c{{bar{c}}} and 4q systems, containing c{{bar{c}}} plus s{{bar{s}}} quarks (or light q{{bar{q}}}) were observed during last decades and recently the LHCb has found a remarkable narrow peak T_{cc}(3875) in the D D^* system. Besides there are several highly excited charmonium-like resonances, which can be treated as the shifted standard charmonium states. We analyze all these groups of the resonances in the mass region (3900–4700) MeV, using relativistic strong coupling theory with possible channel coupling phenomena. For the shifted charmonium states conventional charmonium spectrum is presented, being calculated with the relativistic string Hamiltonian, which does not contain fitting parameters, while for high excitations the universal flattened confining potential is used. It is shown that X(4274), X(4500), X(4700) can be identified as 3,^3P_1, 4,^3P_0, 5,^3P_0 states. The group of exotic states are considered using the Extended Recoupling Model, where two mesons m_1,m_2 transfer into another pair of mesons m_3, m_4 and back (infinite number of times), creating the four-quark resonance. Within this approach the resonances – T_{cc}(3875), Z_c(3900), X(3915), Z_{cs}(3985), X(4014), and X(4140) – can be explained as the exotic four-quark states in the S-wave decay channels.

Gravitating Electron Based on Overrotating Kerr-Newman Solution

We consider a consistent with gravity electron based on the overrotating Kerr-Newman (KH) solution and show that the earlier KH electron models proposed by Carter, Israel and López in 1970–1990 should be modified by the Landau-Ginzburg theory, leading to a superconducting electron model consistent with gravity and quantum theory. Truncated by Israel and López, the second sheet of the KN solution is rearranged and represented in a mirror form as a sheet of the positron, so that the modified KN system forms a quantum electron-positron vacuum interacting with gravity. Regularization of the KN black hole solution creates two new important effects leading to a strong gravitational interaction that acts on the Compton scale contrary to the usual Planck scale of Schwarzschild gravity: (A)—gravitational frame-dragging creates two Wilson loops acting at two boundaries of the modified KN solution, and (B)—formation of the flat superconducting core of the regularized KN solution creates a superconducting electron-positron vacuum state. The Landau-Ginzburg model shows that Wilson loops determine phases of two Higgs fields forming superconducting vacuum state of the modified KN solution, quantum vacuum of the electron-positron pairs. The phases of these Higgs fields correspond to two light-like modes of a classical relativistic ring string. We come to the conclusion that the electron models considered by Israel and López are not complete and must be supplemented by a mirror structure that forms a quantum system consistent with QED.

Branched SL(2,ℤ) duality

We investigate how SL(2,ℤ) duality is realized in nonrelativistic type IIB superstring theory, which is a self-contained corner of relativistic string theory. Within this corner, we realize manifestly SL(2,ℤ)-invariant (p, q)-string actions. The construction of these actions imposes a branching between strings of opposite charges associated with the two-form fields. The branch point is determined by these charges and the axion background field. Both branches must be incorporated in order to realize the full SL(2,ℤ) group. Besides these string actions, we also construct D-instanton and D3-brane actions that manifestly realize the branched SL(2,ℤ) symmetry.

Aspects of Nonrelativistic Strings

We review recent developments on nonrelativistic string theory. In flat spacetime, the theory is defined by a two-dimensional relativistic quantum field theory with nonrelativistic global symmetries acting on the worldsheet fields. This theory arises as a self-contained corner of relativistic string theory. It has a string spectrum with a Galilean dispersion relation, and a spacetime S-matrix with nonrelativistic symmetry. This string theory also gives a unitary and ultraviolet complete framework that connects different corners of string theory, including matrix string theory and noncommutative open strings. In recent years, there has been a resurgence of interest in the non-Lorentzian geometries and quantum field theories that arise from nonrelativistic string theory in background fields. In this review, we start with an introduction to the foundations of nonrelativistic string theory in flat spacetime. We then give an overview of recent progress, including the appropriate target-space geometry that nonrelativistic strings couple to. This is known as (torsional) string Newton–Cartan geometry, which is neither Lorentzian nor Riemannian. We also give a review of nonrelativistic open strings and effective field theories living on D-branes. Finally, we discuss applications of nonrelativistic strings to decoupling limits in the context of the AdS/CFT correspondence.

Note about string theory with deformed dispersion relations

The goal of this short paper is to find Lagrangian for bosonic string with deformed dispersion relation proposed by J. Magueijo and L. Smolin in 2004. We also show that in the preferred case \(f=g\) this Lagrangian reduces into Nambu-Gotto form of relativistic string without modification of the dispersion relation.

KLT factorization of nonrelativistic string amplitudes

We continue our study of the Kawai-Lewellen-Tye (KLT) factorization of winding string amplitudes in [1]. In a toroidal compactification, amplitudes for winding closed string states factorize into products of amplitudes for open strings ending on an array of D-branes localized in the compactified directions; the specific D-brane configuration is determined by the closed string data. In this paper, we study a zero Regge slope limit of the KLT relations between winding string amplitudes. Such a limit of string theory requires a critically tuned Kalb-Ramond field in a compact direction, and leads to a self-contained corner called nonrelativistic string theory. This theory is unitary, ultraviolet complete, and its string spectrum and spacetime S-matrix satisfy nonrelativistic symmetry. Moreover, the asymptotic closed string states in nonrelativistic string theory necessarily carry nonzero windings. First, starting with relativistic string theory, we construct a KLT factorization of amplitudes for winding closed strings in the presence of a critical Kalb-Ramond field. Then, in the zero Regge limit, we uncover a KLT relation for amplitudes in nonrelativistic string theory. Finally, we show how such a relation can be reproduced from first principles in a purely nonrelativistic string theory setting. We will also discuss connections to the amplitudes of string theory in the discrete light cone quantization (DLCQ), a method that is relevant for Matrix theory.

Dual D-brane actions in nonrelativistic string theory

We study worldvolume actions for D-branes coupled to the worldvolume U(1) gauge field and Ramond-Ramond (RR) potentials in nonrelativistic string theory. This theory is a self-contained corner of relativistic string theory and has a string spectrum with a Galilean-invariant dispersion relation. We therefore refer to such D-branes in nonrelativistic string theory as nonrelativistic D-branes. We focus on the bosonic fields in spacetime and also couple the D-branes to general closed string geometry, Kalb-Ramond, and dilaton background fields. We dualize nonrelativistic D-branes by performing a duality transformation on the worldvolume U(1) gauge field and uncover novel dual D-brane actions. This generalizes familiar properties, such as the SL(2, ℤ) duality in Type IIB superstring theory and the relation between Type IIA superstring and M-theory, to nonrelativistic string and M-theory. Moreover, we generalize the limit of string theory, in which nonrelativistic string theory arises, to include RR potentials. This stringy limit induces a codimension-two foliation structure in spacetime. This spacetime geometry is non-Riemannian and known as string Newton-Cartan geometry. In contrast, nonrelativistic M-theory that we probe by dualizing D2- and D4-branes in nonrelativistic string theory arises as a membrane limit of M-theory, and it is coupled to a membrane Newton-Cartan geometry with a codimension-three foliation structure. We also discuss T-duality in nonrelativistic string theory and generalize Buscher rules from earlier work to include RR potentials.

The Laplace Transform of Quantum Gravity

Following analogies with relativistic point particles and Schild strings, we show that the Einstein gravity and its strong coupling regime (or the Planck mass going to zero) are related to each other through a Laplace transform. The Feynman propagator of gravity in the strong coupling regime satisfies a functional diffusion equation in the three-metric space with the evolution parameter being the volume of spacetime. We conjecture that the relationship between both regimes is consistent with the existence of an evolution operator in which time is replaced by the volume of spacetime.

Nonrelativistic Expansion of Closed Bosonic Strings.

We develop a novel approach to nonrelativistic closed bosonic string theory that is based on a string 1/c^{2} expansion of the relativistic string, where c is the speed of light. This approach has the benefit that one does not need to take a limit of a string in a near-critical Kalb-Ramond background. The 1/c^{2}-expanded Polyakov action at next-to-leading order reproduces the known action of nonrelativistic string theory provided that the target space obeys an appropriate foliation constraint. We compute the spectrum in a flat target space, with one circle direction that is wound by the string, up to next-to-leading order and show that it reproduces the spectrum of the Gomis-Ooguri string.