Searcharxiv⌕ Search

arXiv subjects

Jeffrey A. Harvey

Publications and source records attributed to Jeffrey A. Harvey.

At least 55 records · Page 3Linked to original sources
arXiv2007

Standard Model Gauging of the WZW Term: Anomalies, Global Currents and pseudo-Chern-Simons Interactions

The standard model $SU(2)_L\times U(1)_Y$ gauging of the Wess-Zumino-Witten term requires a modified counterterm when background fields, needed to generate the full set of currents, are introduced. The modified counterterm plays an essential role in properly defining covariant global currents and their anomalies. For example, it is required in order to correctly derive the gauge invariant baryon number current and its anomalous divergence. The background fields can also be promoted to a description of the physical spin-1 vector and axial-vector mesons in QCD and the counterterm leads to novel interactions. These are (pseudo-) Chern-Simons terms, such as $ε^{μνρσ} ω_μZ_ν\partial_ρA_σ$ and $ε^{μνρσ} ρ^{\pm}_μW^{\mp}_ν\partial_ρA_σ$ that mediate new interactions between neutrinos and photons at finite baryon density.

hep-th↗
arXiv2007

Anomaly mediated neutrino-photon interactions at finite baryon density

We propose new physical processes based on the axial vector anomaly and described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term, $\sim ε_{μνρσ}ω^μZ^νF^{ρσ}$. This term induces neutrino-photon interactions at finite baryon density via the coupling of the Z-boson to neutrinos. These interactions may be detectable in various laboratory and astrophysical arenas. The new interactions may account for the MiniBooNE excess. They also produce a competitive contribution to neutron star cooling at temperatures >10^9 K. These processes and related axion--photon interactions at finite baryon density appear to be relevant in many astrophysical regimes.

hep-ph↗
arXiv2007

Baryon Number-Induced Chern-Simons Couplings of Vector and Axial-Vector Mesons in Holographic QCD

We show that holographic models of QCD predict the presence of a Chern-Simons coupling between vector and axial-vector mesons at finite baryon density. In the AdS/CFT dictionary, the coefficient of this coupling is proportional to the baryon number density, and is fixed uniquely in the five-dimensional holographic dual by anomalies in the flavor currents. For the lightest mesons, the coupling mixes transverse $ρ$ and $a_1$ polarization states. At sufficiently large baryon number densities, it produces an instability, which causes the $ρ$ and $a_1$ mesons to condense in a state breaking both rotational and translational invariance.

hep-ph↗
arXiv2005

The M2-M5 Brane System and a Generalized Nahm's Equation

We propose an equation that describes M2-branes ending on M5-branes, and which generalizes the description of the D1-D3 system via Nahm's equation. The simplest solution to this equation constructs the transverse geometry in terms of a fuzzy three sphere. We show that the solution passes a number of consistency checks including a consistent reduction to the D1-D3 system, a calculation of the energy of the system, matching to the self-dual string solution in the M5-brane world volume, and a study of simple fluctuations about the ground state configuration. We write down certain terms in the effective action of multiple membranes, which includes a sextic scalar coupling.

hep-th↗
arXiv2005

Worldsheet Instanton Corrections to the Kaluza-Klein Monopole

The Kaluza-Klein monopole is a well known object in both gravity and string theory, related by T-duality to a "smeared" NS5-brane which retains the isometry around the duality circle. As the true NS5-brane solution is localized at a point on the circle, duality implies that the Kaluza-Klein monopole should show some corresponding behavior. In this paper, we express the Kaluza-Klein monopole as a gauged linear sigma model in two dimensions and show that worldsheet instantons give corrections to its geometry. These corrections can be understood as a localization in "winding space" which could be probed by strings with winding charge around the circle.

hep-th↗
arXiv2005

TASI 2003 Lectures on Anomalies

These lecture notes review the structure of anomalies and present some of their applications in field theory, string theory and M theory. They expand on material presented at the TASI 2003 summer school and the 2005 International Spring School on String Theory in Hangzhou, China.

hep-th↗
arXiv2004

The Self-Dual String and Anomalies in the M5-brane

We study the anomalies of a charge $Q_2$ self-dual string solution in the Coulomb branch of $Q_5$ M5-branes. Cancellation of these anomalies allows us to determine the anomaly of the zero-modes on the self-dual string and their scaling with $Q_2$ and $Q_5$. The dimensional reduction of the five-brane anomalous couplings then lead to certain anomalous couplings for D-branes.

hep-th↗
arXiv2002

A Toy Model of the M5-brane: Anomalies of Monopole Strings in Five Dimensions

We study a five-dimensional field theory which contains a monopole (string) solution with chiral fermion zero modes. This monostring solution is a close analog of the fivebrane solution of M-theory. The cancellation of normal bundle anomalies parallels that for the M-theory fivebrane, in particular, the presence of a Chern-Simons term in the low-energy effective U(1) gauge theory plays a central role. We comment on the relationship between the the microscopic analysis of the world-volume theory and the low-energy analysis and draw some cautionary lessons for M-theory.

hep-th↗
arXiv2002

Monstrous branes

We study D-branes in the bosonic closed string theory whose automorphism group is the Bimonster group (the wreath product of the Monster simple group with Z_2). We give a complete classification of D-branes preserving the chiral subalgebra of Monster invariants and show that they transform in a representation of the Bimonster. Our results apply more generally to self-dual conformal field theories which admit the action of a compact Lie group on both the left- and right-moving sectors.

hep-th↗
arXiv2001

Localized Tachyons and RG Flows

We study condensation of closed string tachyons living on defects, such as orbifold fixed planes and Neveu-Schwarz fivebranes. We argue that the high energy density of localized states decreases in the process of condensation of such tachyons. In some cases this means that $c_{eff}$ decreases along the flow; in others, $c_{eff}$ remains constant and the decreasing quantity is a closed string analog, $g_{cl}$, of the ``boundary entropy'' of D-branes. We discuss the non-supersymmetric orbifolds $C/Z_n$ and $C^2/Z_n$. In the first case tachyon condensation decreases $n$ and in some cases connects type II and type 0 vacua. In the second case non-singular orbifolds are related by tachyon condensation to both singular and non-singular ones. We verify that $g_{cl}$ decreases in flows between non-singular orbifolds. The main tools in the analysis are the structure of the chiral ring of the perturbed theory, the geometry of the resolved orbifold singularities, and the throat description of singular conformal field theories.

hep-th↗
arXiv2001

Noncommutative Field Theory and Lorentz Violation

The role of Lorentz symmetry in noncommutative field theory is considered. Any realistic noncommutative theory is found to be physically equivalent to a subset of a general Lorentz-violating standard-model extension involving ordinary fields. Some theoretical consequences are discussed. Existing experiments bound the scale of the noncommutativity parameter to (10 TeV)^{-2}.

hep-th↗
arXiv2001

Komaba Lectures on Noncommutative Solitons and D-Branes

These lectures provide an introduction to noncommutative geometry and its origins in quantum mechanics and to the construction of solitons in noncommutative field theory. These ideas are applied to the construction of D-branes as solitons of the tachyon field in noncommutative open string theory. A brief discussion is given of the K-theory classification of D-brane charge in terms of the K-theory of operator algebras. Based on lectures presented at the Komaba 2000 workshop, Nov. 14-16 2000.

hep-th↗
arXiv2001

Exact Noncommutative Solitons

We find exact solitons in a large class of noncommutative gauge theories using a simple solution generating technique. The solitons in the effective field theory description of open string field theory are interpreted as D-branes for any value of the noncommutativity. We discuss the vacuum structure of open string field theory in view of our results.

hep-th↗
arXiv2000

Tensionless Branes and Discrete Gauge Symmetry

We show that the tensionless branes found recently on non-BPS D-branes using non-commutative field theory are in fact gauge equivalent to the vacuum under a discrete gauge symmetry. We also give a simple construction of the D(2p)-branes in IIA theory starting from a single non-BPS D9-brane.

hep-th↗
arXiv2000

Noncommutative Tachyons and K-Theory

We show that the relation between D-branes and noncommutative tachyons leads very naturally to the relation between D-branes and K-theory. We also discuss some relations between D-branes and K-homology, provide a noncommutative generalization of the ABS construction, and give a simple physical interpretation of Bott periodicity. In addition, a framework for constructing Neveu-Schwarz fivebranes as noncommutative solitons is proposed.

hep-th↗
arXiv2000

The Local Structure of Anomaly Inflow

Anomaly cancellation for M-theory fivebranes requires the introduction of a "bump-form" which smoothes out the five-brane source. We discuss the physical origin of this bump-form in the simpler case of axion strings in 3+1 dimensions and construct it in terms of the radial profile of the fermion zero modes. Our treatment allows for a clearer understanding of the role played by covariant rather than consistent anomalies when anomalies are canceled by inflow from the bulk. We briefly discuss the generalization of these results to fivebrane anomalies in M theory.

hep-th↗
arXiv2000

D-branes and Strings as Non-commutative Solitons

The non-commutative geometry of a large auxiliary $B$-field simplifies the construction of D-branes as solitons in open string field theory. Similarly, fundamental strings are constructed as localized flux tubes in the string field theory. Tensions are determined exactly using general properties of non-BPS branes, and the non-Abelian structure of gauge fields on coincident D-branes is recovered.

hep-th↗