Closed Strings in Misner Space: Cosmological Production of Winding Strings

Misner space, also known as the Lorentzian orbifold $R^{1,1}/boost$, is one of the simplest examples of a cosmological singularity in string theory. In this work, the study of weakly coupled closed strings on this space is pursued in several directions: (i) physical states in the twisted sectors are found to come in two kinds: short strings, which wind along the compact space-like direction in the cosmological (Milne) regions, and long strings, which wind along the compact time-like direction in the (Rindler) whiskers. The latter can be viewed as infinitely long static open strings, stretching from Rindler infinity to a finite radius and folding back onto themselves. (ii) As in the Schwinger effect, tunneling between these states corresponds to local pair production of winding strings. The tunneling rate approaches unity as the winding number $w$ gets large, as a consequence of the singular geometry. (iii) The one-loop string amplitude has singularities on the moduli space, associated to periodic closed string trajectories in Euclidean time. In the untwisted sector, they can be traced to the combined existence of CTCs and Regge trajectories in the spectrum. In the twisted sectors, they indicate pair production of winding strings. (iv) At a classical level and in sufficiently low dimension, the condensation of winding strings can indeed lead to a bounce, although the required initial conditions are not compatible with Misner geometry at early times. (v) The semi-classical analysis of winding string pair creation can be generalized to more general (off-shell) geometries. We show that a regular geometry regularizes the divergence at large winding number.Comment: 46 pages, 5 figures, uses JHEP3.cls; v2: title changed and other minor improvements, final version to appear in JCA

Fine-Grained Chaos in AdS2AdS_2 Gravity

Quantum chaos can be characterized by an exponential growth of the thermal out-of-time-order four-point function up to a scrambling time $\widehat{u}_*$. We discuss generalizations of this statement for certain higher-point correlation functions. For concreteness, we study the Schwarzian theory of a one-dimensional time reparametrization mode, which describes $AdS_2$ gravity and the low-energy dynamics of the SYK model. We identify a particular set of $2k$-point functions, characterized as being both "maximally braided" and "k-OTO", which exhibit exponential growth until progressively longer timescales $\widehat{u}^{(k)}_* = (k-1)\widehat{u}_*$. We suggest an interpretation as scrambling of increasingly fine-grained measures of quantum information, which correspondingly take progressively longer time to reach their thermal values.Comment: 8 pages; v2: minor clarifications, typos, added ref

Effective Field Theory for Chaotic CFTs

We derive an effective field theory for general chaotic two-dimensional conformal field theories with a large central charge. The theory is a specific and calculable instance of a more general framework recently proposed in [1]. We discuss the gauge symmetries of the model and how they relate to the Lyapunov behaviour of certain correlators. We calculate the out-of-time-ordered correlators diagnosing quantum chaos, as well as certain more fine-grained higher-point generalizations, using our Lorentzian effective field theory. We comment on potential future applications of the effective theory to real-time thermal physics and conformal field theory.Comment: 33 pages, 4 figures; v2: minor improvements, added paragraph on higher spin exchanges; v3: minor improvements, added reference, published versio

Patterns Of Distribution Total Suspended Solid (Tss) In River Estuary Kampar Pelalawan

This study was conducted in April 2016 in Kuala Kampar estuary watersPelalawan. The purpose of this study to determine the level of the distributionpattern of suspended solids in the Kampar River Estuary at high tide to the ebband flow toward the post method used in this research is survey method, namelythe study sample was obtained in the field are considered to represent the Islandwaters Mendol, then the samples were analyzed in laboratories to test TSS (TotalSuspended Solid) distribution pattern of total suspended solids in waters KamparRiver Estuary seen that the accumulation of suspended particles at low tide andthe tide heading toward downs, TSS distribution pattern is at the highest value atthe time of ebb tide toward which the values obtained range from 500-1500 mg / l,This indicates that the incoming flow pattern during ebb tide towards very high tothe north. While the TSS distribution pattern that went into the water at low tide tothe obtained value of 700-1100 mg / l where the distribution pattern heading southlocation research

Takhrij Hadith Mengadhankan Bayi Dalam Kitab Tarbiyat Al-awlad Abdullah Nasih Ulwan

Adhan for newborns is one of the traditions of a people based on several hadiths of the Prophet Muhammad. After doing some research on the sanad of the hadith, it can be concluded that the hadith had of three lines: Ahmad, Tirmidhi and Abu Dawud. Hadiths are weak because of all `` As{im ibn Ubaidullah, according to scholars of jarh{ wa ta'di>l, is considered weak and munkar al-hadith. But, the hadith of can be practiced (ma'mu>l bih) and could rise to the level of hadith hasan li ghayrih. This means that echoes adhan in both ears newborns areamong the sunnah, even if these problems get in khilafiyah

A Snapshot of Woody Plants Composition in Byram Permanent Mangrove Forest Reserve

The term mangrove may refer to an ecosystem or individual plants where the distribution of woody plants usually influenced by climate, water salinity, tides, type of soil in the mangrove swamps and environmental activities including development, housing and industrial. Thus only a certain species that can survive under this extreme condition. A study had been conducted in Byram Permanent Mangrove Forest Reserve to provide baseline information on the distribution pattern of plant growth in mangrove area. The main objective of this study is to determine the composition and the distribution pattern of true-mangrove woody plant species. To assess the species composition, the forest reserve nearest to the sea, which run approximately 2.0 km, parallel to the sea, was divided into three main sections (i.e. 600 m each section with a minimum 50 m wide border between the sections). Species enumeration was conducted in 11 plots, where each plot size is 10m x 10m. In general these plots were established in random stratified manner, from the sea towards the terrestrial part of the mangrove forest. In total, we recorded 290 of individual woody plants. The most abundant species in term of occurrences within all zones and forest section is Bruguiera parvifolia

Why is the Matrix Model Correct?

We consider the compactification of M theory on a light-like circle as a limit of a compactification on a small spatial circle boosted by a large amount. Assuming that the compactification on a small spatial circle is weakly coupled type IIA theory, we derive Susskind's conjecture that M theory compactified on a light-like circle is given by the finite $N$ version of the Matrix model of Banks, Fischler, Shenker and Susskind. This point of view provides a uniform derivation of the Matrix model for M theory compactified on a transverse torus $T^p$ for $p=0,...,5$ and clarifies the difficulties for larger values of $p$.Comment: 9 page

Information Recovery From Black Holes

We argue that if black hole entropy arises from a finite number of underlying quantum states, then any particular such state can be identified from infinity. The finite density of states implies a discrete energy spectrum, and, in general, such spectra are non-degenerate except as determined by symmetries. Therefore, knowledge of the precise energy, and of other commuting conserved charges, determines the quantum state. In a gravitating theory, all conserved charges including the energy are given by boundary terms that can be measured at infinity. Thus, within any theory of quantum gravity, no information can be lost in black holes with a finite number of states. However, identifying the state of a black hole from infinity requires measurements with Planck scale precision. Hence observers with insufficient resolution will experience information loss.Comment: First prize in the Gravity Research Foundation Essay Competition, 8 pages, Late