We find nonlocal particle theories with two dimensional conformal symmetry, including examples equivalent to the bosonic open string and closed string. This work provides a new approach to construct solvable consistent backgrounds in string theory.
We consider a nonlocal scalar field theory inspired by the tachyon action in open string field theory. The Lorentz-covariant action is characterized by a parameter $ξ^2$ that quantifies the amount of nonlocality. Restricting to purely time-dependent configurations, we show that a field redefinition perturbative in $ξ^2$ reduces the action to a local two-derivative theory with a $ξ^2$-dependent potential. This picture is supported by evidence that the redefinition maps the wildly oscillating rolling tachyon solutions of the nonlocal theory to conventional rolling in the new scalar potential. Fo…
In the current manuscript we perform a systematic investigation about the effects of nonlocal interaction to the spread of quantum information in many body system. In particular, we have studied how nonlocality influence the existing bound on the growth rate of the commutator involving two local operators, the butterfly velocity. For this purpose, we consider the nonlocal theory on the worldvolume of $N\gg 1$, NS$5$ branes arising in the limit of vanishing string coupling, the `little string theory'. A direct evidence of nonlocality can be realized from the `volume law' behavior for the most d…
In quantum field theory, a consistent prescription to define and deform integration contours in the complex energy plane is needed to evaluate loop integrals and compute scattering amplitudes. In some nonlocal field theories, including string field theory, interaction vertices contain transcendental functions of momenta that can diverge along certain complex directions, thus making it impossible to use standard techniques, such as Wick rotation, to perform loop integrals. The aim of this paper is to investigate the viability of several contour prescriptions in the presence of nonlocal vertices…
In this article, we study Coleman bounce in weakly nonlocal theories which are motivated from string field theory. The kinetic term is extended via an infinite series of high-order derivatives, which comes into play at an energy scale $M$, without introducing any new states or ghosts in the mass spectrum. We calculate the bubble nucleation in thin-wall approximation, treating the system in semi-classical manner. We find that the effect of nonlocal scale $M$ in the theory is to suppress the vacuum tunneling rate from false to true vacuum compared to the standard local bouncing scenario. Likewis…
We discuss the effective action of tachyon in the two dimensional string theory at tree level. We show that already starting from the cubic terms the action is nonlocal and the usually assumed simplest cubic term does not give the correct amplitude. Four point 1PI terms are also discussed.
"Curvepole (2,0)-theory" is a deformation of the (2,0)-theory with nonlocal interactions. A "curvepole" is defined as a two-dimensional generalization of a dipole. It is an object of fixed two-dimensional shape whose boundary is a charged curve that interacts with a two-form gauge field. Curvepole theory was previously only defined indirectly via M-theory. Here we propose a supersymmetric Lagrangian, constructed explicitly up to quartic terms, for an "abelian" curvepole theory, which is an interacting deformation of the free (2,0) tensor mutliplet. This theory contains fields whose quanta are …
We study spontaneous gauge symmetry breaking and the Higgs mechanism in nonlocal field theories. Motivated by the level truncated action of string field theory, we consider a class of nonlocal field theories with an exponential factor of the d'Alembertian attached to the kinetic and mass terms. Modifications of this kind are known to make mild the UV behavior of loop diagrams and thus have been studied not only in the context of string theory but also as an alternative approach to quantum gravity. In this paper we argue that such a nonlocal theory potentially includes a ghost mode near the non…
Considering an exactly solvable local quantum theory of a scalar field interacting with a $δ$-shaped time-dependent potential we calculate the Bogoliubov coefficients analytically and determine the spectrum of created particles. We then show how these considerations, when suitably generalized to a specific nonlocal "infinite-derivative" quantum theory, are impacted by the presence of nonlocality. In this model, nonlocality leads to a significant resonant amplification of certain modes, leaving its imprint not only in the particle spectrum but also in the total number density of created particl…
A New Formulation of the Initial Value Problem for Nonlocal Theories
有许多理由认为,局部性在微观尺度上是被破坏的,例如,在基本运动方程中存在无穷级数的高阶导数。这种类型的非定域性导致改进的紫外行为,新颖的宇宙动力学,是弦论的一般预测。另一方面,从根本上讲,非局部模型充满了复杂性,包括不稳定性和建立初始值问题的复杂性。我们研究了一类有趣的非局部模型的初值问题的结构。我们提倡一种新的新的公式,其中柯西表面是“涂抹”的基础规模的非局部性,使通常的概念,初始数据在t=0被替换为“初始函数”定义在-M^{-1} \leq t \leq 0,其中M是基础规模的非局部性。集中在一些具体的例子,从弦论和宇宙学,我们表明,这种数学重新制定了令人惊讶的影响,众所周知的稳定性问题。对于D-膜衰变在一个线性介子的背景下,我们能够表明,不稳定的方向相空间不能访问从一个物理上合理的初始函数。因此,在这个模型中不稳定解的先前例子对应于非物理的初始条件,在初始值问题的旧公式中被混淆的观察。我们还讨论了这种方法的非局部宇宙学模型的含义。