One-loop finiteness of the string theory on the T22/G manifold

1987 ◽  
Vol 65 (9) ◽  
pp. 1149-1153
Author(s):  
Da-Xi Li

We explicitly evaluate the one-loop amplitude of the string theory on the T22/G manifold and show that the theory is finite at the one-loop level. The twisted sectors play a crucial role in the proof of the modular-group invariance.

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Luis F. Alday ◽  
Xinan Zhou

Abstract We demonstrate the simplicity of AdS5× S5 IIB supergravity at one loop level, by studying non-planar holographic four-point correlators in Mellin space. We develop a systematic algorithm for constructing one-loop Mellin amplitudes from the tree-level data, and obtain a simple closed form answer for the $$ \left\langle {\mathcal{O}}_2^{SG}{\mathcal{O}}_2^{SG}{\mathcal{O}}_p^{SG}{\mathcal{O}}_p^{SG}\right\rangle $$ O 2 SG O 2 SG O p SG O p SG correlators. The structure of this expression is remarkably simple, containing only simultaneous poles in the Mellin variables. We also study the flat space limit of the Mellin amplitudes, which reproduces precisely the IIB supergravity one-loop amplitude in ten dimensions. Our results provide nontrivial evidence for the persistence of the hidden conformal symmetry at one loop.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ashoke Sen

Abstract In a recent paper, Balthazar, Rodriguez and Yin found remarkable agreement between the one instanton contribution to the scattering amplitudes of two dimensional string theory and those in the matrix model to the first subleading order. The comparison was carried out numerically by analytically continuing the external energies to imaginary values, since for real energies the string theory result diverges. We use insights from string field theory to give finite expressions for the string theory amplitudes for real energies. We also show analytically that the imaginary parts of the string theory amplitudes computed this way reproduce the full matrix model results for general scattering amplitudes involving multiple closed strings.


Author(s):  
David Montenegro ◽  
B. M. Pimentel

We examine the generalized quantum electrodynamics as a natural extension of the Maxwell electrodynamics to cure the one-loop divergence. We establish a precise scenario to discuss the underlying features between photon and fermion where the perturbative Maxwell electrodynamics fails. Our quantum model combines stability, unitarity, and gauge invariance as the central properties. To interpret the quantum fluctuations without suffering from the physical conflicts proved by Haag’s theorem, we construct the covariant quantization in the Heisenberg picture instead of the Interaction one. Furthermore, we discuss the absence of anomalous magnetic moment and mass-shell singularity.


2010 ◽  
Vol 2010 (10) ◽  
Author(s):  
Florian Staub ◽  
Werner Porod ◽  
Björn Herrmann

Ramus ◽  
1986 ◽  
Vol 15 (2) ◽  
pp. 83-92
Author(s):  
Dale Chant

In the Iphigeneia at Aulis role and role inversion are paramount concerns. Indeed it could be contended that in this play we find Euripides' clearest and best defined account of human (and divine) variability. Agamemnon, Menelaos, Achilleus, Iphigeneia, and even, in the final analysis, Artemis, all take positions and attitudes diametrically opposed to those initially adopted. Moreover, the basic thrust behind these movements in position and attitude is the same for each of these characters. All are concerned, in one way or another, with the saving or destruction of Iphigeneia, a situation which most emphatically includes Iphigeneia herself. For on the one hand she wildly supplicates to be saved, while on the other she gladly offers her body to the blade. In addition, Iphigeneia plays a crucial role in greater destructions. If she is destroyed by Agamemnon's and the army's actions, then Greece is destroyed in turn by her (Agamemnon's and the Greeks' final triumph is a ‘Pyrrhic’ victory at best), a situation made all the more ironic by her affected stance of saviour to the fatherland. In Iphigeneia's case, however, the discrepancy between intention and the consequences of action is innocent enough. The play gives no hint that she is at all aware of the irony implicit in her actions. But such lack of awareness is not postulated with regard to Agamemnon, Menelaos and Achilleus. The duplicities and hypocrisies of these three have been the subject of much analysis, and it is at least a critical commonplace to observe that they are characterised in a way more reminiscent of the sour end of everyday life than of the due proprieties associated with heroic, or Homeric, behaviour.


2019 ◽  
Vol 34 (16) ◽  
pp. 1950123 ◽  
Author(s):  
Damiano Anselmi

Several particles are not observed directly, but only through their decay products. We consider the possibility that they might be fakeons, i.e. fake particles, which mediate interactions but are not asymptotic states. A crucial role to determine the true nature of a particle is played by the imaginary parts of the one-loop radiative corrections, which are affected in nontrivial ways by the presence of fakeons in the loop. The knowledge we have today is sufficient to prove that most non-directly observed particles are true physical particles. However, in the case of the Higgs boson the possibility that it might be a fakeon remains open. The issue can be resolved by means of precision measurements in existing and future accelerators.


2009 ◽  
Vol 21 (10) ◽  
pp. 1197-1240 ◽  
Author(s):  
HISHAM SATI ◽  
URS SCHREIBER ◽  
JIM STASHEFF

We study the cohomological physics of fivebranes in type II and heterotic string theory. We give an interpretation of the one-loop term in type IIA, which involves the first and second Pontrjagin classes of spacetime, in terms of obstructions to having bundles with certain structure groups. Using a generalization of the Green–Schwarz anomaly cancellation in heterotic string theory which demands the target space to have a String structure, we observe that the "magnetic dual" version of the anomaly cancellation condition can be read as a higher analog of String structure, which we call Fivebrane structure. This involves lifts of orthogonal and unitary structures through higher connected covers which are not just 3- but even 7-connected. We discuss the topological obstructions to the existence of Fivebrane structures. The dual version of the anomaly cancellation points to a relation of string and Fivebrane structures under electric-magnetic duality.


2011 ◽  
Author(s):  
Nodoka Yamanaka ◽  
Toru Sato ◽  
Takahiro Kubota ◽  
Atsushi Hosaka ◽  
Kanchan Khemchandani ◽  
...  
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2018 ◽  
Vol 175 ◽  
pp. 11014
Author(s):  
Kenji Hieda ◽  
Aya Kasai ◽  
Hiroki Makino ◽  
Hiroshi Suzuki

The gradient flow [1–5] gives rise to a versatile method to construct renor-malized composite operators in a regularization-independent manner. By adopting this method, the authors of Refs. [6–9] obtained the expression of Noether currents on the lattice in the cases where the associated symmetries are broken by lattice regularization. We apply the same method to the Noether current associated with supersymmetry, i.e., the supercurrent. We consider the 4D N = 1 super Yang–Mills theory and calculate the renormalized supercurrent in the one-loop level in the Wess–Zumino gauge. We then re-express this supercurrent in terms of the flowed gauge and flowed gaugino fields [10].


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