Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userDyons, Superstrings, and Wormholes
109
0
0.0
(
0
)
Authors
Edward A. Olszewski
Ask ChatGPT about the research
No Arabic abstract
We construct dyon solutions on a collection of coincident D4-branes, obtained by applying the group of T-duality transformations to a type I SO(32) superstring theory in 10 dimensions. The dyon solutions, which are exact, are obtained from an action consisting of the non-abelian Dirac-Born-Infeld action and Wess-Zumino-like action. When one of the spatial dimensions of the D4-branes is taken to be vanishingly small, the dyons are analogous to the t Hooft/Polyakov monopole residing in a 3+1 dimensional spacetime, where the component of the Yang-Mills potential transforming as a Lorentz scalar is re-interpreted as a Higgs boson transforming in the adjoint representation of the gauge group. We next apply a T-duality transformation to the vanishingly small spatial dimension. The result is a collection of D3-branes not all of which are coincident. Two of the D3-branes which are separated from the others acquire intrinsic, finite, curvature and are connected by a wormhole. The dyon possesses electric and magnetic charges whose values on each D3-brane are the negative of one another. The gravitational effects, which arise after the T-duality transformation, occur despite the fact that the Lagrangian density from which the dyon solutions have been obtained does not explicitly include the gravitational interaction. These solutions provide a simple example of the subtle relationship between the Yang-Mills and gravitational interactions, i.e. gauge/gravity duality.
rate research
Read More
We construct dyon solutions in SU(N) with topological electric and magnetic charge. Assuming a |Phi|^4-like potential for the Higgs field we show that the mass of the dyons is relatively insensitive to the coupling parameter lambda characterizing the potential. We then apply the methodology of constructing dyon solutions in SU(N) to G2. In order to define the electromagnetic field consistently in the manner that we propose we find that dyon solutions exist only when G2 is considered under the action of its maximal and regular subgroup SU(3). In this case we find two different types of dyons, one of which has properties identical to dyons in SU(3). The other dyon has some properties which are seemingly atypical, e.g. the magnetic charge g_m = 4 pi 3/e, which differs from the t Hooft/Polyakov monopole where g_m = 4 pi 1/e.
Cosmic strings are predicted by many field-theory models, and may have been formed at a symmetry-breaking transition early in the history of the universe, such as that associated with grand unification. They could have important cosmological effects. Scenarios suggested by fundamental string theory or M-theory, in particular the popular idea of brane inflation, also strongly suggest the appearance of similar structures. Here we review the reasons for postulating the existence of cosmic strings or superstrings, the various possible ways in which they might be detected observationally, and the special features that might discriminate between ordinary cosmic strings and superstrings.
We study a class of decoherence process which admits a 3 dimensional holographic bulk. Starting from a thermo-field double dual to a wormhole, we prepare another thermo-field double which plays the role of environment. By allowing the energy flow between the original and environment thermo-field double, the entanglement of the original thermo-field double eventually decoheres. We model this decoherence by four-boundary wormhole geometries, and study the time-evolution of the moduli parameters to see the change of the entanglement pattern among subsystems. A notable feature of this holographic decoherence processes is that at the end point of the processes, the correlations of the original thermo-field double are lost completely both classically and also quantum mechanically. We also discuss distinguishability between thermo-field double state and thermo mixed double state, which contains only classical correlations, and construct a code subspace toy model for that.
We consider random superstrings of type IIB in $d$-dimensional space. The discretized action is constructed from the supersymetric matrix model, which has been proposed as a constructive definition of superstring theory. Our action is invariant under the local N=2 super transformations, and doesnt have any redundant fermionic degrees of freedom.
In AdS/CFT partition functions of decoupled copies of the CFT factorize. In bulk computations of such quantities contributions from spacetime wormholes which link separate asymptotic boundaries threaten to spoil this property, leading to a factorization puzzle. Certain simple models like JT gravity have wormholes, but bulk computations in them correspond to averages over an ensemble of boundary systems. These averages need not factorize. We can formulate a toy version of the factorization puzzle in such models by focusing on a specific member of the ensemble where partition functions will again factorize. As Coleman and Giddings-Strominger pointed out in the 1980s, fixed members of ensembles are described in the bulk by $alpha$-states in a many-universe Hilbert space. In this paper we analyze in detail the bulk mechanism for factorization in such $alpha$-states in the topological model introduced by Marolf and Maxfield (the MM model) and in JT gravity. In these models geometric calculations in $alpha$ states are poorly controlled. We circumvent this complication by working in $textit{approximate}$ $alpha$ states where bulk calculations just involve the simplest topologies: disks and cylinders. One of our main results is an effective description of the factorization mechanism. In this effective description the many-universe contributions from the full $alpha$ state are replaced by a small number of effective boundaries. Our motivation in constructing this effective description, and more generally in studying these simple ensemble models, is that the lessons learned might have wider applicability. In fact the effective description lines up with a recent discussion of the SYK model with fixed couplings arXiv:2103.16754. We conclude with some discussion about the possible applicability of this effective model in more general contexts.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
