The hep-th papers on the arXiv.ORG are much more interesting today than they are on the average day, even on the average Tuesday (which usually attracts more papers, submitted during the weekend and on Mondays).
I declare the paper by Zwiebach and Kiermeier to be the most interesting paper. But we will mention all 22 papers and classify them into groups.
String field theory
Michael Kiermaier and Barton Zwiebach discuss one-loop amplitudes calculated from string field theory, using Schnabl gauge. There are several "field-theoretical" approaches where the moduli can be extracted in various ways. For example, in the light-cone gauge, they are identified as functions of the interaction times and the fractions of p+, the longitudinal momentum, divided between various virtual strings.
In Siegel gauge, they are expressed as functions of the Schwinger parameters.
The same thing is true in Schnabl gauge. But there is one shocking surprise. In the previous two pictures, the functions mapping the moduli in different languages are messy. In Schnabl gauge, they can be explicitly calculated in closed form as functions of extra degrees of freedom resulting from the special midpoint of the open string! So Schnabl gauge is "simpler" and more natural to calculate amplitudes - and maybe even off-shell amplitudes - than both light-cone gauge and the old Siegel gauge of covariant string field theory.
Yutaka Baba, Nobuyuki Ishibashi, Koichi Murakami also study string field theory and they calculate the annulus diagram, too. They construct a state describing a collection of D-branes at different places in an OSp theory and calculate the annulus diagram out of these concepts, obtaining the same result of the first-quantized setup.
Information loss
Samir Mathur has figured out a new catchy slogan explaining how the information is preserved during black hole evaporation. With horizons, the information should be lost. For his fuzzballs, it is preserved. His reconciliation of these two answers is that a black hole has a finite probability of tunneling into a fuzzball (a small probability times many channels is finite). So already before the hole radiates a significant fraction of the mass, it is already turned into a fuzzball. It sounds sexy except that there is some kind of double-counting here.
If he describes the black hole microstates as fuzzball configurations, he shouldn't talk about "ordinary" old-fashioned black hole states at the same moment, should he? He is really tunneling from one description to another, isn't he? Also, I don't know whether the infalling observers notice the tunneling. In my opinion, they shouldn't.
Another case of tunneling: landscape
Matthew C Johnson and Magdalena Larfors discuss tunneling in a toy model of the landscape, namely the complex structure moduli space of the mirror quintic. They find two basins of attraction and no slow-roll inflation. For multi-dimensional moduli spaces, they approximately construct tunneling instantons, finding that they are typically thick-wall instantons, and discuss various consequences.
Inflation and cosmology
Steven Weinberg proves a theorem dictating how to calculate tree amplitudes in the in-in formalism for inflation from a generating function that solves certain classical equations. A lot of new results from Steven Weinberg...
Masato Minamitsuji discusses FRW-like cosmology in KK braneworlds with extra dimensions. The result seems to coincide with the early RS II cosmology. I am not sure whether I understand the problem being solved here.
String and SUSY phenomenology
Mary Gaillard and Bruno Zumino wrote a basic review of supersymmetry, its history, its relationships to string theory, and the reasons why these tools are likely to be relevant for physics beyond the Standard Model. The paper was dedicated to Julius Wess who died recently. Yes, he was the superpartner of Zumino even though some people could have expected Bruno Zumon.
Pure geometry
Tsuyoshi Houri, Takeshi Oota, Yukinori Yasui write a proof that completes their paper we discussed previously. Now they prove that their generalized Kerr-NUT-deSitter solutions are the most general geometries that preserve the rank-2 conformal CKY tensor.
Dmitri V. Gal'tsov and Nikolai G. Scherbluk present a technique to generate solutions to low-energy (supergravity) equations of M-theory on T^6 such as various black hole and black ring solutions. It is important for them to parameterize the cosets nicely.
Calabi-Yau structures
Michael R. Douglas and Gonzalo Torroba show how to calculate the kinetic terms of various 4D fields obtained as modes on Calabi-Yau manifolds, e.g. the complex structure modulus of a deformed conifold with flux (Klebanov-Strassler solution inside a larger compact Calabi-Yau space). Previous power-law guesses are confirmed qualitatively but their numbers are slightly different.
Constantin Bachas, Massimo Bianchi, Ralph Blumenhagen, Dieter Lust, Timo Weigand look at various Calabi-Yau compactifications with orientifolds but without vector structure, their consistency, and their T-duals (intersecting IIA braneworlds).
Amihay Hanany and Noppadol Mekareeya encounter the Calabi-Yau geometry in a context that is related to the following category - super-QCD. The geometry, the Calabi-Yau cone over a weighted projective variety, appears as a classical moduli space of a super-QCD theory. But the main goal is actually to count gauge-invariant operators in various theories, using generating functions, Hilbert series, and the Molien-Weyl formula - in the context of SU and (by orientifolding) SO and Sp groups.
Holography and AdS/CFT
Yasuaki Hikida and Volker Schomerus prove the FZZ duality: the cigar conformal field theory is now officially equivalent to the Sine-Liouville model! It is enough to check all the tachyon vertex operators. They use some methods based on the sl(2) Langlands program.
M.Bonini, G.M.Cicuta, E.Onofri study the spectrum of the dilatation operator in the post-BMN description of gauge theory, using the algebraic definition by Minahan et al., using the scalar and single-trace character of the objects. A lot of eigenstates is found.
Michal P. Heller, R. Loganayagam, Michal Spalinski, Piotr Surowka, Samuel E. Vazquez use a new parameterization to remove a divergence from the late time expansion of a boost-invariant plasma in AdS/CFT of the N=4 super Yang-Mills.
Matthew M. Roberts and Sean A. Hartnoll use AdS4/CFT3 to study superconductors, finding a pseudogap at low temperatures and a positive Hall conductivity.
R. Fukuda "derives" the 't Hooft - Kogut-Susskind dielectric model of confinement from the stability of the condensed vacuum and I don't understand how such a proof is possible and whether there is some circular reasoning involved.
Cosmological billiards
Marc Henneaux, Daniel Persson, Daniel H. Wesley decided to study cosmological billiards systematically. They look at various things such as the Coxeter group to see whether a particular case exhibits chaotic dynamics or not, among other questions.
Membrane minirevolution
Hai Lin claims to construct new 3-algebras that are positively definite, by decoupling a negative mode from an indefinite solution. The author also discusses Kač-Moody, infinite-dimensional versions of 3-algebras (including central charges that appear automatically).
Shamik Banerjee and Ashoke Sen write something that I realized since the first papers about the Bagger-Lambert-Gustavsson Lagrangian: the extra scalar field is the position of the M2-brane center of mass in cylindrical coordinates.
Assorted papers
A. Lewis Licht is motivated by the unparticle physics but ends up investigating open Wilson lines (needed to make the unparticle action gauge-invariant). It is claimed that the Mandelstam derivative of an open Wilson line is "mathematically inconsistent". What can this statement about a derivative mean? What is really meant is that Mandelstam has omitted one term. But I don't understand the paper.
Kazuo Fujikawa studies the non-Hermitean character of the radial component of the momentum, P_r, in polar coordinates and its links to the extra power-law repulsive potential that appears in the path-integral description. For different dimensions, there are different qualitative behaviors. I can't quite imagine that there is something new - beyond the homework in courses of quantum mechanics - in this paper.
I declare the paper by Zwiebach and Kiermeier to be the most interesting paper. But we will mention all 22 papers and classify them into groups.
String field theory
Michael Kiermaier and Barton Zwiebach discuss one-loop amplitudes calculated from string field theory, using Schnabl gauge. There are several "field-theoretical" approaches where the moduli can be extracted in various ways. For example, in the light-cone gauge, they are identified as functions of the interaction times and the fractions of p+, the longitudinal momentum, divided between various virtual strings.
In Siegel gauge, they are expressed as functions of the Schwinger parameters.
The same thing is true in Schnabl gauge. But there is one shocking surprise. In the previous two pictures, the functions mapping the moduli in different languages are messy. In Schnabl gauge, they can be explicitly calculated in closed form as functions of extra degrees of freedom resulting from the special midpoint of the open string! So Schnabl gauge is "simpler" and more natural to calculate amplitudes - and maybe even off-shell amplitudes - than both light-cone gauge and the old Siegel gauge of covariant string field theory.
Yutaka Baba, Nobuyuki Ishibashi, Koichi Murakami also study string field theory and they calculate the annulus diagram, too. They construct a state describing a collection of D-branes at different places in an OSp theory and calculate the annulus diagram out of these concepts, obtaining the same result of the first-quantized setup.
Information loss
Samir Mathur has figured out a new catchy slogan explaining how the information is preserved during black hole evaporation. With horizons, the information should be lost. For his fuzzballs, it is preserved. His reconciliation of these two answers is that a black hole has a finite probability of tunneling into a fuzzball (a small probability times many channels is finite). So already before the hole radiates a significant fraction of the mass, it is already turned into a fuzzball. It sounds sexy except that there is some kind of double-counting here.
If he describes the black hole microstates as fuzzball configurations, he shouldn't talk about "ordinary" old-fashioned black hole states at the same moment, should he? He is really tunneling from one description to another, isn't he? Also, I don't know whether the infalling observers notice the tunneling. In my opinion, they shouldn't.
Another case of tunneling: landscape
Matthew C Johnson and Magdalena Larfors discuss tunneling in a toy model of the landscape, namely the complex structure moduli space of the mirror quintic. They find two basins of attraction and no slow-roll inflation. For multi-dimensional moduli spaces, they approximately construct tunneling instantons, finding that they are typically thick-wall instantons, and discuss various consequences.
Inflation and cosmology
Steven Weinberg proves a theorem dictating how to calculate tree amplitudes in the in-in formalism for inflation from a generating function that solves certain classical equations. A lot of new results from Steven Weinberg...
Masato Minamitsuji discusses FRW-like cosmology in KK braneworlds with extra dimensions. The result seems to coincide with the early RS II cosmology. I am not sure whether I understand the problem being solved here.
String and SUSY phenomenology
Mary Gaillard and Bruno Zumino wrote a basic review of supersymmetry, its history, its relationships to string theory, and the reasons why these tools are likely to be relevant for physics beyond the Standard Model. The paper was dedicated to Julius Wess who died recently. Yes, he was the superpartner of Zumino even though some people could have expected Bruno Zumon.
Pure geometry
Tsuyoshi Houri, Takeshi Oota, Yukinori Yasui write a proof that completes their paper we discussed previously. Now they prove that their generalized Kerr-NUT-deSitter solutions are the most general geometries that preserve the rank-2 conformal CKY tensor.
Dmitri V. Gal'tsov and Nikolai G. Scherbluk present a technique to generate solutions to low-energy (supergravity) equations of M-theory on T^6 such as various black hole and black ring solutions. It is important for them to parameterize the cosets nicely.
Calabi-Yau structures
Michael R. Douglas and Gonzalo Torroba show how to calculate the kinetic terms of various 4D fields obtained as modes on Calabi-Yau manifolds, e.g. the complex structure modulus of a deformed conifold with flux (Klebanov-Strassler solution inside a larger compact Calabi-Yau space). Previous power-law guesses are confirmed qualitatively but their numbers are slightly different.
Constantin Bachas, Massimo Bianchi, Ralph Blumenhagen, Dieter Lust, Timo Weigand look at various Calabi-Yau compactifications with orientifolds but without vector structure, their consistency, and their T-duals (intersecting IIA braneworlds).
Amihay Hanany and Noppadol Mekareeya encounter the Calabi-Yau geometry in a context that is related to the following category - super-QCD. The geometry, the Calabi-Yau cone over a weighted projective variety, appears as a classical moduli space of a super-QCD theory. But the main goal is actually to count gauge-invariant operators in various theories, using generating functions, Hilbert series, and the Molien-Weyl formula - in the context of SU and (by orientifolding) SO and Sp groups.
Holography and AdS/CFT
Yasuaki Hikida and Volker Schomerus prove the FZZ duality: the cigar conformal field theory is now officially equivalent to the Sine-Liouville model! It is enough to check all the tachyon vertex operators. They use some methods based on the sl(2) Langlands program.
M.Bonini, G.M.Cicuta, E.Onofri study the spectrum of the dilatation operator in the post-BMN description of gauge theory, using the algebraic definition by Minahan et al., using the scalar and single-trace character of the objects. A lot of eigenstates is found.
Michal P. Heller, R. Loganayagam, Michal Spalinski, Piotr Surowka, Samuel E. Vazquez use a new parameterization to remove a divergence from the late time expansion of a boost-invariant plasma in AdS/CFT of the N=4 super Yang-Mills.
Matthew M. Roberts and Sean A. Hartnoll use AdS4/CFT3 to study superconductors, finding a pseudogap at low temperatures and a positive Hall conductivity.
R. Fukuda "derives" the 't Hooft - Kogut-Susskind dielectric model of confinement from the stability of the condensed vacuum and I don't understand how such a proof is possible and whether there is some circular reasoning involved.
Cosmological billiards
Marc Henneaux, Daniel Persson, Daniel H. Wesley decided to study cosmological billiards systematically. They look at various things such as the Coxeter group to see whether a particular case exhibits chaotic dynamics or not, among other questions.
Membrane minirevolution
Hai Lin claims to construct new 3-algebras that are positively definite, by decoupling a negative mode from an indefinite solution. The author also discusses Kač-Moody, infinite-dimensional versions of 3-algebras (including central charges that appear automatically).
Shamik Banerjee and Ashoke Sen write something that I realized since the first papers about the Bagger-Lambert-Gustavsson Lagrangian: the extra scalar field is the position of the M2-brane center of mass in cylindrical coordinates.
Assorted papers
A. Lewis Licht is motivated by the unparticle physics but ends up investigating open Wilson lines (needed to make the unparticle action gauge-invariant). It is claimed that the Mandelstam derivative of an open Wilson line is "mathematically inconsistent". What can this statement about a derivative mean? What is really meant is that Mandelstam has omitted one term. But I don't understand the paper.
Kazuo Fujikawa studies the non-Hermitean character of the radial component of the momentum, P_r, in polar coordinates and its links to the extra power-law repulsive potential that appears in the path-integral description. For different dimensions, there are different qualitative behaviors. I can't quite imagine that there is something new - beyond the homework in courses of quantum mechanics - in this paper.
One-loop moduli in Schnabl gauge
![One-loop moduli in Schnabl gauge]()
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May 26, 2008
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