A Group Blog on Physics

- Postdoctoral Position at the interface of Algebra, Conformal Field Theory and String Theory (Dec 5, 2006)
- Postdoc position in algebra, CFT and strings.
- The n-Category Café (Aug 17, 2006)
- New group blog: “The n-Category Cafe”.
- Synthetic Transitions (Jul 28, 2006)
- On deriving 2-connection transition laws using synthetic differential geometry.
- Quillen's Superconnections -- Functorially (Jul 26, 2006)
- On how to interpret the superconnections appearing on brane/anti-brane configurations in terms of functorial transport.
- K-Theory for Dummies, II (Jul 26, 2006)
- Some remarks on K-theory and D-branes.
- Brodzki, Mathai, Rosenberg & Szabo on D-Branes, RR-Fields and Duality (Jul 20, 2006)
- Mathai et al give a detailed analysis of the nature of D-branes, RR-charges and T-duality using and extending the topological/algebraic machinery known from “topological T-duality”.
- 2-Palatini (Jul 19, 2006)
- Some remarks on formulations of (super)gravity in terms of n-connections.
- Herbst, Hori & Page on Equivalence of LG and CY (Jul 18, 2006)
- Hori and Herbst on equivalence of Landau-Ginzburg and Calabi-Yau TFT models using gauged linear sigma models.
- Gomi on Reps of p-Form Connection Quantum Algebras (Jul 14, 2006)
- Gomi on the construction of projective unitary reps of centrally extended groups of p-form connections.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, VI (Jul 13, 2006)
- More detials on elliptic curves, formal groups and “classical” elliptic cohomology.
- Freed, Moore, Segal on p-Form Gauge Theory, II (Jul 11, 2006)
- On Heisenberg groups appearing in the quantization of higher chiral gauge theories.
- Freed, Moore, Segal on p-Form Gauge Theory, I (Jul 10, 2006)
- Some aspects of recent work by Freed, Moore and Segal on the quantum theory of abelian p-form fields and the grading of the Hilbert space by electric and magnetic flux modulo torsion.
- How many Circles are there in the World? (Jul 8, 2006)
- On 2-torsors for suspended U(1).
- Gomi on Chern-Simons terms and central extensions of gerbe gauge groups (Jul 5, 2006)
- Gomi on Chern-Simons field theories in higher dimensions and central extension of gerbe gauge groups.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, V (Jun 28, 2006)
- Part V of a seminar on elliptic cohomology and 2-vector bundles. Review of relations between elliptic cohomology and strings.
- Gukov on Surface Operators in Gauge Theory and Categorification (Jun 27, 2006)
- Gukov relates knot theory to categorified quantum mechanics and the like.
- Kapranov and Getzler on Higher Stuff (Jun 22, 2006)
- Lecture notes of talks by Kapranov on noncommutative Fourier transformation and by Getzler on Lie theory of L_oo algebras.
- Varieties and Schemes for Dummies, Part III (Jun 22, 2006)
- Still more notes on elements of algebraic geometry.
- Varieties and Schemes for Dummies, Part II (Jun 22, 2006)
- More notes on elements of algebraic geometry.
- Sharpe on Derived Categories and Strings on Stacks (Jun 21, 2006)
- Slides of Eric Sharpe’s ESI talk on derived categories, strings on stacks and renormalization group flow.
- Varieties and Schemes for Dummies, Part I (Jun 20, 2006)
- Notes on elements of algebraic geometry.
- Kapustin on SYM, Mirror Symmetry and Langlands, III (Jun 17, 2006)
- The third part of the lecture.
- Kapustin on SYM, Mirror Symmetry and Langlands, II (Jun 17, 2006)
- Second part of A. Kapustin’s talk.
- Soibelman on NCG of CFT and Mirror Symmetry (Jun 16, 2006)
- Soibelman on collaps of CFTs on noncommutative target spaces.
- Kapustin on SYM, Mirror Symmetry and Langlands, I (Jun 15, 2006)
- Kapustin lectures on mirror symmetry in twisted compactified SYM, realizing geometric Langlands.
- Roberts on Nonabelian Cohomology (Jun 15, 2006)
- An old reference to a paper by Roberts on nonabelian cohomology.
- Kontsevich Lectures on Mirror Symmetry, I (Jun 14, 2006)
- Kontsevich lectures on mirror symmetry I: TQFTs and CohFTs.
- Castellani on FDA in SuGra: gauge 3-group of M-Theory (Jun 12, 2006)
- Castellani uses free differential algebra, and implictly Line n-algebra connections, for understanding the symmetries of 11D supergravity.
- Homological Mirror Symmetry Literature (Jun 10, 2006)
- Some literature on homological mirror symmetry and related issues.
- Mathai on T-Duality IV: Distler on CFT Checks (Jun 10, 2006)
- Jacques Distler comments on CFT checks of topological T-duality.
- Crane-Sheppeard on 2-Reps (Jun 9, 2006)
- On linear 2-reps as discussed by Crane and Sheppeard.
- ESI Workshop on Homological Mirror Symmetry (Jun 4, 2006)
- Kontsevich lectures at ESI on Homological Mirror Symmetry
- Going the Wrong Way - for Dummies (Jun 2, 2006)
- The definition of the pullback of sheaves of modules.
- Mathai on T-Duality, III: Algebraic Formulation (Jun 2, 2006)
- Mathai on elements of the C-star algebraic formulation of T-duality.
- Mathai on T-Duality, II: T-dual K-classes by Fourier-Mukai (Jun 2, 2006)
- First part of V. Mathai’s talk on topological T-duality: T-dual K-classes by means of Fourier-Mukai transformation.
- Mathai on T-Duality, I: Overview (Jun 2, 2006)
- Some elements of T-duality in the context of noncommutative topology. Part I: some context.
- Fourier-Mukai, T-Duality and other linear 2-Maps (Jun 1, 2006)
- Examples for linear 2-maps.
- 2-Spectral Theory, Part II (May 30, 2006)
- Complete 2-bases of 2-eigenvectors (with an eye on Hecke eigensheaves and duality defects).
- Some Links (May 29, 2006)
- A paper on TQFT and String Topology, some lecture notes on derived categories and a paper on TCFT.
- 2-Spectral Theory, Part I (May 29, 2006)
- Does a categorified spectral theorem connect duality defects in CFT with diagonizable Hecke-like 2-operators?
- 2-Metric Geometry (May 25, 2006)
- Categorifying Lawvere’s conception of metric spaces.
- Bunke on H, Part III (May 23, 2006)
- Second part of U. Bunke’s talk on how to realize twisted deRham cohomology in terms of cohomology on gerbes.
- Bunke on H, Part II (May 23, 2006)
- Transcript of talk by U. Bunke on twisted cohomology and cohomology on gerbes.
- Bunke on H, Part I (May 23, 2006)
- U. Bunke et. al propose a (more) natural home for the twisted deRham cohomology appearing in Kalb-Ramond flux backgrounds.
- The FRS Theorem on RCFT (May 19, 2006)
- Statement of the FRS theorem in rational conformal field theory.
- Hecke Eigensheaves and higher Eigenvectors (May 15, 2006)
- More details on how Hecke eigensheaves are related to categorified eigenvectors.
- Pantev on Langlands, II (May 10, 2006)
- Pantev lectures on Langlands duality, D-branes and quantization, part II.
- Pantev on Langlands, I (May 9, 2006)
- Pantev lectures on Langlands duality, D-branes and quantization.
- Eigenbranes and CatLinAlg (May 7, 2006)
- The concept of eigenbranes, which appears in the context of geometric Langlands, and the categorified linear algebra of FRS.
- Formal HQFT (May 4, 2006)
- Porter and Turaev on formal HQFT.
- Talk in Bonn on String 2-Group (Apr 26, 2006)
- Talk on the String 2-Group in Bonn.
- Huybrechts on Branes in K3, II (Apr 21, 2006)
- Huybrechts analyzes the relation between topological and BPS branes on K3 surfaces, part II.
- Huybrechts on Branes in K3, I (Apr 21, 2006)
- Huybrechts analyzes the relation between topological and BPS branes on K3 surfaces.
- Jurco on Gerbes and Stringy Applications (Apr 19, 2006)
- Jurco reviews some facts concerning nonabelian gerbes in string theory.
- A Note on RCFT and Quiver Reps (Apr 18, 2006)
- A note on how the structure of RCFT is encoded in something very similar to a quiver representation.
- (R)CFT on more general 2-Categories (Apr 18, 2006)
- RCFTs can apparently be defined as 2-functors on 2-paths in Riemann surfaces. Can this be generalized to other domain 2-categories?
- More Vietri Talks (Apr 16, 2006)
- Talks on topological membranes and twisted K-theory
- RR-Forms and Algebroids (Apr 12, 2006)
- RR forms and free graded differential algebras.
- Generalized Worldsheets? (Apr 12, 2006)
- What is known about generalizations of world sheets away from the concept of manifolds?
- Picard and Brauer 2-Groups (Apr 5, 2006)
- On the Picard 2-group and the Brauer 2-group of a monoidal category.
- More by Bartels on 2-Bundles (Apr 4, 2006)
- Refined notes by Toby Bartels on 2-bundles.
- Particles, Strings and the Early Universe in Hamburg (Apr 4, 2006)
- A planned collaborative research center in Hamburg, on strings, HEP and cosmology.
- Categorified Gauge Theory in Chicago (Apr 4, 2006)
- Conference with emphasis on categorified gauge theory, covering gerbes and the String group.
- String Localization, Once Again (Mar 29, 2006)
- Recap of string localization.
- Exotic String Statistics (Mar 28, 2006)
- On generalizations of braid group statistics from points to strings.
- Gerbes and Quantization (Mar 28, 2006)
- Report on a paper on gerbes and quantization.
- Cats in MathPhys (Mar 26, 2006)
- List of applications of category theory in mathematical physics and string theory.
- Stevenson, Henriques on String(n) (Mar 22, 2006)
- Stevenson and Henriques have articles on the String group.
- Remarks on 2-Reps (Mar 16, 2006)
- More on 2-representations of the String(n) group.
- Vertex Algebras et al. - Some Literature (Mar 14, 2006)
- Literature on vertex algebras and related topics.
- Gerbes and Quantum Field Theory (Mar 14, 2006)
- Mickelsson on the role of gerbes in the study of anomalies in quantum field theory.
- Remarks on String(n) (Mar 11, 2006)
- Is Stolz/Teichner’s String-connection a 2-connection in an associated 2-bundle?
- What IS a superfield, really? (Mar 7, 2006)
- On the true (functorial) nature of superfields.
- Hilbert Uniformization of Moduli Space (Mar 7, 2006)
- On a result by Boedigheimer on Hilbert uniformization.
- nEFT at Schloss Mickeln, Part II (Mar 6, 2006)
- Talk by Johannes Ebert on CFT partition functions and modular forms.
- nEFT at Schloss Mickeln, Part I (Mar 4, 2006)
- Talk by E. Markert on concepts and results in describing generalized cohomology in terms of euclidean field theory. Part I. Mostly pesonal remarks on the general program.
- Superpoints (Mar 2, 2006)
- First notes from a workshop on elliptic objects.
- Kapranov and Ganter on 2-Characters (Feb 27, 2006)
- Ganter and Kapranov have a paper on traces and characters of 2-categorical representations of groups.
- Graphs, Operads and Renormalization (Feb 23, 2006)
- On a category of graphs appearing in Riemann surface moduli spaces and in renormalization theory.
- On Transport Theory (Feb 17, 2006)
- Overview of the theory of n-transport.
- 1st Northern German String workshop (Feb 12, 2006)
- A string workshop at the ZMP.
- Problemi Attuali di Fisica Teorica 06 (Feb 9, 2006)
- This year’s meeting in Vietri.
- Workshop on Gerbes, Groupoids and QFT (Feb 9, 2006)
- Announcement of a workshop on gerbes and QFT.
- FRS Reviews (Feb 8, 2006)
- Two new reviews on FRS formalism.
- Special Ambidextrous Adjunctions (Feb 8, 2006)
- Question on special ambidextrous adjunctions.
- Philosophy of Real Mathematics (Feb 7, 2006)
- David Corfield on Jacob Lurie’s survey of elliptic cohomology.
- Lauda & Pfeiffer on Open-Closed Topological Strings, II (Feb 6, 2006)
- Lauda and Pfeiffer on open/closed topological strings from state sums.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, IV (Feb 5, 2006)
- First session, third part.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, III (Feb 5, 2006)
- First session, second part.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, II (Feb 3, 2006)
- First session, first part.
- Seminar on 2-Vector Bundles and Elliptic Cohomology, I (Feb 2, 2006)
- Review of the 2-vector approach towards elliptic cohomology. Part I.
- Exploring the Blogosphere (Feb 2, 2006)
- Articles on math/physics weblogs.
- Orbifold String Topology: Paths in Smooth Categories (Feb 2, 2006)
- A 2-functorial conception of Lupercio & Uribe’s loop groupoid.
- Moerdijk on Orbifolds, III (Feb 1, 2006)
- Transcript of second of two lectures by I. Moerdijk on orbifolds.
- Moerdijk on Orbifolds, II (Jan 31, 2006)
- Transcript of first of two lectures by I. Moerdijk on orbifolds.
- Moerdijk on Orbifolds, I (Jan 31, 2006)
- I. Moerdijk lectures on the theory of orbifolds.
- Spans, 2-Hilbert Spaces and Module Categories (Jan 27, 2006)
- How to obtain 2-Hilbert spaces from span categories.
- (String) Physics from (Higher) Algebra, II (Jan 24, 2006)
- Some revisions on the program of categorifying quantum mechanics and relating it to string physics.
- TCFT, Part I (Jan 10, 2006)
- Some basic ideas of TCFT.
- (String) Physics from (Higher) Algebra (Jan 9, 2006)
- One further refinement of the tale called ‘Strings from categorified quantum mechanics.’
- Nekrasov Lecture Online II (Jan 5, 2006)
- The third session of Nikita Nekrasov’s lecture in Jerusalem. Some news on the Cech description of the pure spinor string.
- Nekrasov Lecture Online I (Jan 4, 2006)
- Quicktime video of Nikita Nekrasov’s lectures on the pure spinor superstring is available online.
- Confusion and Connes Fusions (Jan 4, 2006)
- Elements of Connes fusion.
- Bimodules, Adjunctions and the Internal Hom, Part II (Jan 3, 2006)
- More on bimodules, adjunctions, module categories and internal homs.
- Bimodules, Adjunctions and the Internal Hom, Part I (Jan 2, 2006)
- Notes on certain phenomena concerning algebra objects and adjunctions in tensor categories.
- More by Gustavsson on Non-Abelian Strings (Jan 2, 2006)
- More by A. Gustavsson on nonabelian strings
- Winter School on Elliptic Objects (Dec 24, 2005)
- Winter School on Elliptic Objects
- Müger on Doplicher-Roberts (Dec 23, 2005)
- Mueger has a new proof of Doplicher Roberts.
- Equivariant Structures on Gerbes (Dec 23, 2005)
- Some literature on gerbes on orbifolds.
- Unoriented Strings and Gerbe Holonomy (Dec 22, 2005)
- New preprint on gerbe holonomy over unoriented surfaces.
- 3D TFT Literature (Dec 20, 2005)
- Literature on 3D TFT and its relation to 2D CFT.
- Lauda on Frobenius Algebras and Open Topological Strings (Dec 15, 2005)
- Lauda on Frobenius algebras and open topological strings and membranes.
- Frobenius Algebras and 2D QFT (Dec 15, 2005)
- On Frobenius algebras in 2D TFT and CFT.
- Topological Strings from 2-Transport (Dec 14, 2005)
- Fukuma-Hosono-Kawai TFT is obtained from 2-transport in Vect.
- E. Sharpe on Derived Categories (Dec 13, 2005)
- Encyclopedia article on derived categories by E. Sharpe.
- D-Branes in Landau-Ginzburg Models (Dec 8, 2005)
- Some elementary background on B-branes in LG models.
- NABGs from 2-Transport I: Synthetic Bibundles (Dec 7, 2005)
- Deriving nonabelian bundle gerbes from 2-functor 1-morphisms.
- 2-Connections on 2-Bundles (Dec 2, 2005)
- 2-connections on 2-bundles once again
- "Area Metric" Manifolds (Nov 29, 2005)
- On Schuller and Wohlfarth on area metric geometry and strings.
- Line-2-Bundles and Bundle Gerbes (Nov 22, 2005)
- On parallel transport of string in line-2-bundles.
- CFT and SLE (Nov 15, 2005)
- Notes on the SLE approach to CFT.
- Lauda & Pfeiffer on Open-Closed Topological Strings (Nov 13, 2005)
- Lauda and Pfeiffer fill some gaps in the rigorous understanding of open topological strings.
- Strings on Stacks II (Nov 9, 2005)
- More on Eric Sharpe and Tony Pantev on strings on stacks.
- Strings on Stacks I (Nov 8, 2005)
- Notes on E. Sharpe’s work on strings on stacks.
- 2-Equivariance and "Weak Pullback" (Nov 7, 2005)
- On equivariant 2-bundles and strings on orbifolds.
- Classical, Canonical, Stringy (Nov 2, 2005)
- A stringy 3-form generalization of 2-form symplectic canonical mechanics.
- Gerbes, strings, and Nambu brackets (Nov 1, 2005)
- How are symplectic forms and Poisson brackets related to closed 3-forms and string physics?
- Sheaves of CDOs (Oct 31, 2005)
- Literature on Cech-methods in CFT.
- Plasma-Ball Duals of Black Holes (Oct 27, 2005)
- Aharony on plasma-ball duals to black holes and Berkooz on Q-ball excitations in MSSM as inflaton candidates.
- ZMP Colloquium, Thursday: Nekrasov on Pure Spinor Superstring (Oct 20, 2005)
- A talk by N. Nekrasov on the pure-spinor superstring and its apparent relation to gerbes.
- Kalkkinen: Nonabelian Gerbes from twisted SYM (Oct 18, 2005)
- Kalkkinen has a new paper where he points out relations between twisted SYM on 5-branes and nonabelian gerbes.
- Synthetic Differential Geometry and Surface Holonomy (Oct 11, 2005)
- Synthetic differential geometry and its use in the literature on higher gauge theory.
- What is "the" Gerbe of a 2-Bundle? (Oct 5, 2005)
- An observation on how a gerbe arises from a 2-bundle in an intrinsic (rather than cocyclic) way.
- Literature on Exotic R4s (Sep 27, 2005)
- Question on literature on exotic R4s.
- Center for MathPhys Opening Colloquium in Hamburg (Sep 23, 2005)
- Colloquium on mathematical aspects of string and field theory in Hamburg.
- A. Gustavsson on Surface Holonomy (Sep 23, 2005)
- A new proposal for nonabelian surface holonomy by Andreas Gustavsson.
- Gerbes, Algebroids and Groupoid Bundles, the emerging Picture (Sep 2, 2005)
- The big picture of gerbes, algebroids, groupoid bundles and some generalized geometry.
- CFT, Gerbes and K-Theory in Oberwolfach, VII (Aug 24, 2005)
- You’ll have noticed that I failed to report on the talks of the last two days in Oberwolfach, either…
- Lecture Notes on Higher Gauge Theory (Aug 22, 2005)
- John Baez’s lecture notes on Higher Gauge Theory, Homotopy Theory and n-Categories,
- CFT, Gerbes and K-Theory in Oberwolfach, VI (Aug 20, 2005)
- Jurco’s talk on classification of gerbes.
- CFT, Gerbes and K-Theory in Oberwolfach, V (Aug 17, 2005)
- Wednesday in Oberwolfach.
- CFT, Gerbes and K-Theory in Oberwolfach, IV (Aug 16, 2005)
- Tuesday in Oberwolfach: stacks, gerbes, M-theory and K-theory.
- CFT, Gerbes and K-Theory in Oberwolfach, III (Aug 15, 2005)
- Talks on gerbes in WZW models and some other stuff.
- CFT, Gerbes and K-Theory in Oberwolfach, II (Aug 15, 2005)
- Monday morning at Oberwolfach: M-theory for mathematicians and 2-gerbes for supergravity.
- K-theory for dummies, I (Aug 12, 2005)
- A list of some basic concepts in K-theory.
- CFT, Gerbes and K-Theory in Oberwolfach, I (Aug 12, 2005)
- On a workshop in Oberwolfach next week and some details on joint ideas with Igor Bakovic.
- Q: Open Strings in KR Background (Jul 23, 2005)
- How to understand the coupling of the KR field to open strings.
- Costello on Open Topological Strings (Jul 17, 2005)
- On a paper about open topological strings by K. Costello.
- Talks in Hamburg, Lectures in Bad Honnef (Jul 15, 2005)
- Random notes on HQFT and BCFT.
- 2-Holonomy in Terms of 2-Torsors (Jul 5, 2005)
- Details on 2-holonomy in terms of 2-torsors and some pointers to the Streetfest conference.
- From Loop Space Mechanics to Nonabelian Strings (Jun 23, 2005)
- My thesis.
- String(n), Part II (May 18, 2005)
- Review of issues related to String(n).
- String(n), Part I (May 18, 2005)
- Review of issues related to String(n).
- Nonabelian Weak Deligne Hypercohomology (May 17, 2005)
- Generalizing Deligne cohomology to the nonabelian and weak case.
- PSM and Algebroids, Part V (May 16, 2005)
- Transitions in a p-bundle in terms of algebroid morphisms.
- PSM and Algebroids, Part IV (May 13, 2005)
- Last time I discussed how Lie pp-algebroids (and hence Lie pp-algebras) and dg-algebras on graded vector spaces of maximal…
- PSM and Algebroids, Part III (May 4, 2005)
- On the equivalence between algebroids, dg algebras and Lie p-algebras, the definition of algebroid YM theories and the relation to generalized geometry and abelian p-bundles and p-gerbes.
- PSM and Algebroids, Part II (Apr 29, 2005)
- How Courant algebroids gives rise to L_infinity algebras.
- Akhmedov comments (Apr 20, 2005)
- More on Akhmedov’s ideas concerning 2D TFTs.
- Weak NABG (Apr 15, 2005)
- On weak nonabelian bundle gerbes.
- PSM and Algebroids, Part I (Apr 14, 2005)
- There seem to be interesting relations of the Poisson σ\sigma-model (PSM) and of Lie algebroids to all kinds of…
- Open topological strings (Apr 13, 2005)
- Some literature on open topological strings.
- Lessons from low Dimensions (Apr 9, 2005)
- I am currently visting a CFT workshop at University of Bonn, Lessons from low Dimensions - the many Aspects of Conformal Field Theory.
- New preprint: From Loop Groups to 2-Groups (and the String Group) (Apr 7, 2005)
- We have a new preprint demonstrating a relation between weak Lie 2-algebras, 2-groups coming from centrally extended loop groups and the group String(n).
- 2-NCG: First Refinement (Apr 1, 2005)
- Is 2-NCG an April Fool’s joke?
- Akhmedov: Nonabelian 2-Holonomy using TFT (Mar 31, 2005)
- Discussion of Akhmedov’s paper on 2-holonomy.
- Derived Categories for Dummies, Part IV (Mar 22, 2005)
- How branes and strings are described by the derived category of coherent sheaves.
- Derived Categories for Dummies, Part III (Mar 20, 2005)
- Elementary aspects of derived categories of quiver representations – plus a remark on how this relates to 2-bundles.
- Derived Categories for Dummies, Part II (Mar 19, 2005)
- Review of the definition of derived functors.
- Rasetti: Quantum Computers based on TQFT (Mar 19, 2005)
- Rasetti proposes that topological quantum field theories may be models for P=NP-quantumcomputers.
- Talk at IIASS: Nonabelian Strings (Mar 16, 2005)
- Slides for my talk at the IIASS on nonabelian strings.
- Derived categories for dummies, Part I (Mar 13, 2005)
- Some facts about derived categories. And an open question…
- Quiver reps and vector 2-bundles (Mar 11, 2005)
- A note on how quiver reps seem to be related to vector 2-bundles as in Baas,Dundas&Rognes.
- What's next (Feb 24, 2005)
- I have just returned from my two week visit of John Baez’s group at UC Riverside, which was extremely nice…
- Project: 2-NCG (Feb 15, 2005)
- A discussion of categorified NCG and its relation to superstrings.
- Conversation with Kea: Categorified NCG (Feb 11, 2005)
- Conversation with Kea on NCG and categorification.
- Categorified Gauge Theory and M-Theory (Feb 9, 2005)
- Does categorification of gauge theory know about the dimensions of the fundamental objects in M-theory?
- 2-Holonomy LEGO (Feb 3, 2005)
- Category LEGO used to define and discuss global nonabelian 2-holonomy.
- New paper: 2-Connections on 2-Bundles (Dec 30, 2004)
- Mine and John Baez’s paper ‘2-connections on 2-bundles’ is available as a preprint.
- Re: Categorified Gauge Theory (Dec 27, 2004)
- Comments on how nonabelian surface holonomy relates to nonabelian volume integrals.
- Nonabelian Self-Duality (Dec 15, 2004)
- This is a followup to Peter Woit’s recent blog entry Langlands Program and Physics. There, Peter mentions the following…
- Re: Category Theory and Physics (Dec 3, 2004)
- Reply to Lubos’s comments on the last entry on categories and strings.
- Categorified Points: Strings as Morphisms (Nov 24, 2004)
- Over at sci.math.research there are some comments on categorification and its relation to string theory. Of course categories, being…
- Weak groups, hard computation (Nov 18, 2004)
- Results on 2-bundles with coherent structure 2-groups.
- Nonabelian gerbes with connection and curving from 2-bundles with 2-holonomy (Nov 3, 2004)
- A proof that a 2-bundle with 2-holonomy defines a nonabelian gerbe with certain connection and curving.
- Thoughts on n-cube Scaling on 5-Branes (Oct 27, 2004)
- Some thoughts on possible formal reasons for the n-cube scaling of degrees of freedom on 5-branes.
- Re: Self-dual strings and M5-brane anomalies (Oct 22, 2004)
- Comment on Lubos’ comment on Berman&Harvey’s Self-Dual String Anomalies.
- 2-bundles (Oct 19, 2004)
- Finally there is a paper on 2-bundles.
- Tensionless strings and Polyakov's loops (Oct 14, 2004)
- Aspects of tensionless strings.
- DDF=Pohlmeyer known in 1981 (Sep 16, 2004)
- Readers of this blog will recall that I was involved in some thinking about Pohlmeyer invariants. It all started with…
- States of string in non-abelian 2-form background (Sep 12, 2004)
- Strings in non-abelian 2-form backgrounds again: Some conceptual issues.
- r-flatness = 2-associativity (Aug 30, 2004)
- I am further discussing loop space-, surface- and and 2-group-holonomy with those interested. While trying to convince the 2-group-theorists…
- News release on emergent string spacetime (Aug 27, 2004)
- My friend Rüdiger Vaas, who is working as a science journalist for the german science magazin Bild der Wissenschaft,…
- On loop space and 2-group holonomy (Aug 27, 2004)
- A pdf with my notes on the relation between loop space holonomy and 2-group holonomy is now available.
- Why does 2-group theory miss surface holonomies with nonvanishing B+F? (Aug 24, 2004)
- One more observation about the relation between 2-group theory and loop space holonomy.
- 1+1D LQG is really about boundary states (Aug 23, 2004)
- What does LQG have to do with boundary states?
- Super-Pohlmeyer invariants and boundary states for non-abelian gauge fields (Aug 20, 2004)
- I have just submitted the following to the preprint server: Urs Schreiber: Super-Pohlmeyer invariants and boundary states for non-abelian…
- Everybody agrees on the non-abelian boundary state! (Aug 19, 2004)
- I realize that the different definitions of the non-abelian boundary state in the literature all agree.
- Microscopic relation between loop space connections and 2-group holonomies (Aug 18, 2004)
- I discuss how loop space holonomies and 2-group holonomies are related.
- Escape from the Fog (Aug 16, 2004)
- Report from vacation in Norway - and the inevitable remarks on some string theory.
- On Holiday (Jul 30, 2004)
- I’ll be on holiday the next two weeks.
- A bird, a plane? No, super-Pohlmeyer! (Jul 27, 2004)
- Recently I had talked about how I think Pohlmeyer invariants are related to boundary states of D-branes with gauge…
- More remarks on flat loop space connections (Jul 23, 2004)
- More comments on flat connections on loop space and their relation to surface holonomies.
- Three ways to loop flatness (Jul 22, 2004)
- Today I was contacted by Luiz Agostinho Ferreira who kindly called my attention to the paper Orlando Alvarez &…
- To loose or not to loose information (Jul 22, 2004)
- Comment on Hawking’s talk on the black hole information loss problem.
- Talking to ’t Hooft about tossing TVs (Jul 19, 2004)
- Summary of a talk by ’t Hooft.
- Mathematical loop space literature (Jul 15, 2004)
- Readers of my writings will have noticed that I mention the tem loop space from time to time. Now, I…
- Nonabelian B-field equations of motion (Jul 13, 2004)
- I try to derive the equations of motion of a nonabelian B-field from boundary state divergences.
- Not Abelian - but Flat (Jul 12, 2004)
- The crucial condition for non-abelian 2-form connections is their flatness in loop space.
- Scandinavian but not Abelian (Jul 9, 2004)
- I have attended a conference in Karlstad and thought about nonabelian 2-forms.
- From Paris to Karlstad (via Bonn) (Jul 4, 2004)
- I am preparing for talks in Bonn and Karlstad.
- Cabinet de Curiosites dot com - STRINGS 04 (Jun 30, 2004)
- The annual string theory conference is taking place at College de France in Paris this year. Fortunately this is…
- Nonabelian 2-form connection from SCFT deformation (Jun 21, 2004)
- I show how the loop space connection of a nonabelian 2-form arises from the obvious SCFT deformation.
- Pohlmeyer invariants and states of the IIB matrix model (Jun 13, 2004)
- Discussion of a relation between Pohlmeyer invariants and distributions of D(-1) branes which solve the IIB matrix model.
- Open string backgrounds from boundary state deformations (Jun 11, 2004)
- Review of some aspects of the boundary state deformation technique studied by Koji Hashimoto.
- String entropy and black hole correspondence (Jun 10, 2004)
- Brief summary of aspects of the string/black hole correspondence principle.
- Experiments probing quantum gravity (Jun 10, 2004)
- List of experiments that try to probe quantum gravity in one way or another.
- Sigh. (Jun 7, 2004)
- Bogdanov and Bogdanov have done it again.
- CFTs from OSFT! (May 19, 2004)
- The relation between classical SFT solutions and (boundary) conformal field theories is further discussed.
- Referee reports on SCFT deformations and Pohlmeyer invariants (May 13, 2004)
- Readers of this weblog will recall that we had discussed here two drafts which I have meanwhile submitted to JHEP….
- Talk: N=2 NCG, fields and strings (May 3, 2004)
- I am giving a talk at the Hamburg theory seminar on discrete NCG, fields and strings.
- CFTs from OSFT? (Apr 29, 2004)
- A comment about a relation between string field theory and deformed CFTs on the worldsheet.
- Billiards at half-past E10 (Apr 26, 2004)
- Aspects of sigma-models on Kac-Moody groups.
- New York, New York (Apr 23, 2004)
- I have visited Ioannis Giannakis in New York, discussing superfconformal deformations.
- Power Supply (Apr 14, 2004)
- I am visiting the AEI in Potsdam, discussing Pohlmeyer invariants and issues of quantization of string.
- Billiards, random matrices, M-theory and all that (Apr 8, 2004)
- I am currently at a seminar on quantum chaos and related stuff. You cannot enjoy meetings like these without…
- Notions of string-localization (Mar 30, 2004)
- Bert Schroer made me aware of the notion of ‘string-localized fields’, which are quite different from ordinary string fields.
- Visualization of Superstring States (Mar 18, 2004)
- Heuristic visualization of the massless states of superstring.
- DPG Symposium 2004 (Mar 13, 2004)
- I am on my way to the spring conference of the German Physical Society, the Frühjahrstagung der Deutschen Physikalischen Gesellschaft…
- Introductory String Theory Seminar (Mar 11, 2004)
- List of introductory literature for string theory.
- Poll for sci.physics.strings (Mar 9, 2004)
- Probably everybody has seen the Call for Votes for the creation of a new USENET newsgroup with the proposed…
- Simple but not trivial (Mar 8, 2004)
- Discussion of a paper concerned with constant R-R 2-form background in NSR formalism.
- Before the flood (Mar 5, 2004)
- On how to approach Type II strings by abstract differential calculus.
- [Admin.] How to participate in the String Coffee Table dicussion (Feb 21, 2004)
- A list of tips and tricks for how to participate in the discussion at the String Coffee Table.
- The joy of IIB Matrix Models (Feb 20, 2004)
- As readers of sci.physics.research might remember, a while ago I had learned about the IIB Matrix Model and had…
- Torsion Gravity from String Theory (Feb 15, 2004)
- I was asked by A. Pelster, who has worked on torsion gravity together with H. Kleinert and F. Hehl,…
- [Review] DDF states (Jan 29, 2004)
- The recent discussion about attempts to quantize the (super-)string by studying its algebra of classical invariants (i.e. of phase…
- Pohlmeyer charges, DDF states and string-gauge duality (Jan 29, 2004)
- It’s half past two in the morning here in central Europe and a can’t sleep because my brain is thinking…
- Thiemann's quantization of the Nambu-Goto action (Jan 27, 2004)
- Aspects of the recent paper by Th. Thiemann on the ‘LQG-string’ are discussed.
- The search for discrete differential geometry (Jan 26, 2004)
- At first it may look like a trivial problem whose solution should have been known for ages, being used…
- [Review] Type II on AdS_3, Part I: Lightcone spectrum (Jan 26, 2004)
- The calculation of the exact lightcone spectrum of superstrings on AdS_3 x S^3 is reviewed as a preparation for a demonstration of perturbative calculations of the same thing using curvature corrections to the Penrose limit.
- [Exercise] Canonical analysis of D-string action (Jan 15, 2004)
- The author tries to work his way through the canonical anaylsis of the D-string action. Help him! :-)
- Classical deformations of 2d SCFTs - Part II: Algebra Isomorphisms (Dec 30, 2003)
- It has been shown in Part I (see also hep-th/0401175) that the modes of the KK-deformed exterior derivative d…
- Classical deformations of 2d SCFTs - Part I: Loop space (Dec 23, 2003)
- Motivated by the representation of the classical super Virasoro constraints as generalized Dirac-Kaehler constraints (d±d +)|ψ⟩=0(\mathbf{d} \pm \mathbf{d}^+)|\psi\rangle =…
- Cosmic F- and D-strings (Dec 17, 2003)
- In the paper Copeland, Myers, Polchinski, Cosmic F- and D-strings the authors discuss cosmic strings and F/D-strings on the same…
- deformation of SCFTs (Dec 15, 2003)
- This environment is very inspiring, I’ll start with a couple of questions right away: :-) Is there anything known about…

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