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80160240320 · Jun 202019922001200920172026
48 results for Eta term

Paper establishes a new formula for Atiyah-Patodi-Singer index using eta invariants.

problem Calculating the Atiyah-Patodi-Singer index without invertibility of boundary operator.
method Using an asymptotic gluing formula for eta invariants and a splitting principle.
result Formula expressing index in terms of eta invariants of domain-wall massive Dirac operators.

The eta invariant appears regularly in index theorems but is known to be directly computable from the spectrum only in certain examples of locally symmetric spaces of compact type. In this work, we derive some general formulas useful for calculating the eta invariant on closed manifolds. Specifically, we study the eta …

2012-10-30abs ↗pdf ↗

We extend the Atiyah, Patodi, and Singer index theorem for first order differential operators from the context of manifolds with cylindrical ends to manifolds with periodic ends. This theorem provides a natural complement to Taubes' Fredholm theory for general end-periodic operators. Our index theorem is expressed in t…

2011-05-02abs ↗pdf ↗

Derives an index formula for families of end-periodic Dirac operators.

problem Calculating the index of families of end-periodic Dirac operators.
method Using the renormalized Chern character and Fourier-Laplace transform of the Bismut superconnection.
result Establishes an index formula involving a new end-periodic eta form.

Neural model outperforms ETAS in forecasting Central Apennines earthquakes.

problem Short-term seismicity forecasting with incomplete data.
method Extended a neural network model to the magnitude domain, using it to forecast earthquakes above a target magnitude threshold.
result Neural model outperforms ETAS at lower magnitude thresholds, due to its robustness to missing data.

In previous work, we introduced eta invariants for even dimensional manifolds. It plays the same role as the eta invariant of Atiyah-Patodi-Singer, which is for odd dimensional manifolds. It is associated to K1K^1 representatives on even dimensional manifolds and is closely related to the so called WZW theory in physic…

2012-05-02abs ↗pdf ↗

In 1993, Bismut and Zhang establish a mod Z embedding formula of Atiyah-Patodi-Singer reduced eta invariants. In this paper, we explain the hidden mod Z term as a spectral flow and extend this embedding formula to the equivariant family case. In this case, the spectral flow is generalized to the equivariant chern chara…

2017-06-21abs ↗pdf ↗

The integral of the top dimensional term of the multiplicative sequence of Pontryagin forms associated to an even formal power series is calculated for special Riemannian metrics on the unit ball of a hermitean vector space. Using this result we calculate the generating function of the reduced Dirac and signature eta-i…

2017-07-20abs ↗pdf ↗

Using adiabatic limits of Eta invariants, Rho invariants of the total space of a fiber bundle are investigated. One concern is to formulate the aspects of local index theory for families of Dirac operator in terms of the odd signature operator, and place known results in a context which permits the treatment of Rho inv…

2009-07-21abs ↗pdf ↗

In this paper, we define the equivariant eta form of Bismut-Cheeger for a compact Lie group and establish a formula about the functoriality of equivariant eta forms with respect to the composition of two submersions.

2015-05-17abs ↗pdf ↗

Using H. Donnelly result from the article "Eta Invariants for G-Spaces" we calculate the eta invariants of the signature operator for almost all 7-dimensional flat manifolds with cyclic holonomy group. In all cases this eta invariants are an integer numbers. The article was motivated by D. D. Long and A. Reid article "…

2010-01-08abs ↗pdf ↗

Let A(t)A(t) be an elliptic, product-type suspended (which is to say parameter-dependant in a symbolic way) family of pseudodifferential operators on the fibres of a fibration φφ with base Y.Y. The standard example is A+itA+it where AA is a family, in the usual sense, of first order, self-adjoint and elliptic pseudodiffe…

2009-05-01abs ↗pdf ↗

We extend the theory of the universal eta-invariant to the case of relative bordism groups of manifolds with boundaries. This allows the construction of secondary descendants of the universal eta-invariant. We obtain an interpretation of Laures' f-invariant as an example of this general construction. As an aside we imp…

2014-03-09abs ↗pdf ↗

We study the eta-invariants of links and show that in many cases they form link concordance invariants, in particular that many eta-invariants vanish for slice links. This result contains and generalizes previous invariants by Smolinsky and Cha--Ko. We give a formula for the eta-invariant for boundary links. In several…

2003-06-09abs ↗pdf ↗

Paper generalizes spectral flow formulas for compact Lie group actions.

problem Generalizing spectral flow formulas for compact Lie group actions.
method Equivariant version of Dai-Zhang higher spectral flow, embedding formula, adiabatic limit formula for Atiyah-Patodi-Singer eta invariants.
result Generalization of eta forms to equivariant Bismut-Cheeger eta forms.

We prove an asymptotic bound on the eta invariant of a family of coupled Dirac operators on an odd dimensional manifold. In the case when the manifold is the unit circle bundle of a positive line bundle over a complex manifold, we obtain precise formulas for the eta invariant.

2014-03-27abs ↗pdf ↗

Researchers compute Floer homotopy types and eta invariants for Seifert 3-manifolds.

problem Computing Floer homotopy types and eta invariants for Seifert 3-manifolds.
method Floer homology, Seiberg-Witten Floer homotopy type, adiabatic connections, spin^c-Dirac operators, eta invariants, orbifold pin^c-connections.
result Floer homotopy types are suspensions of S^0, and Seifert 3-manifolds are L-spaces.

Paper extends variational formula for Bismut-Cheeger eta form, proving key theorems in K-theory.

problem Extending variational formula for Bismut-Cheeger eta form without kernel bundle assumption.
method Twisting spinc^c Dirac operators by isomorphic vector bundles, proving Z2\mathbb{Z}_2-graded additivity.
result Analytic index in differential K-theory is a well-defined group homomorphism, and Riemann-Roch-Grothendieck theorem in R/Z\mathbb{R}/\mathbb{Z} K-theory.

We consider families of Dirac operators on the unit interval which depend on parameters via boundary conditions. We study the associated eta forms and Maslov cocyles. With this simple example we show how previous results of Lesch/Woiciechowski and the first author on the eta invariant of cylinders generalize to the fam…

1997-01-13abs ↗pdf ↗

We prove two geometric index theorems for a family of first-order elliptic operators over a manifold with boundary by computing eta form representatives for the Chern character classes of the index bundle. The eta forms occur as relative and regularized traces on infinite-dimensional vector bundles realized as the limi…

2002-11-22abs ↗pdf ↗

In the paper we consider the theory of elliptic operators acting in subspaces defined by pseudodifferential projections. This theory on closed manifolds is connected with the theory of boundary value problems for operators violating Atiyah-Bott condition. We prove an index formula for elliptic operators in subspaces de…

1999-07-06abs ↗pdf ↗

Study eta invariant on non-compact manifolds with positive scalar curvature.

problem Proving geometric formulas and index theorems for uniformly positive scalar curvature metrics.
method Using Dirac-Schrödinger operators and relative eta invariant.
result New geometric formula for spectral flow and index formula for uniformly positive scalar curvature metrics.

We study eta-Einstein geometry as a class of distinguished Riemannian metrics on contact metric manifolds. In particular, we use a previous solution of the Calabi problem for Sasakian geometry to prove the existence of eta-Einstein structures on many different compact manifolds, including exotic spheres. We also relate…

2004-06-30abs ↗pdf ↗

Derives numerical formulas for elliptic differential operators on specific groupoids.

problem Index problem of elliptic differential operators on boundary groupoids.
method Similar to Moroianu and Nistor's renormalized trace approach, focusing on eta and Atiyah-Singer terms.
result For q3q \geq 3, KK-theoretic and Fredholm indices are given by the Atiyah-Singer term.

Let B_n be the Artin braid group on n strings with standard generators sigma_1, ..., sigma_{n-1}, and let SB_n be the singular braid monoid with generators sigma_1^{+-1}, ..., sigma_{n-1}^{+-1}, tau_1, ..., tau_{n-1}. The desingularization map is the multiplicative homomorphism eta: SB_n --> Z[B_n] defined by eta(sigma…

2003-06-30abs ↗pdf ↗

On a spin manifold with conformal cusps, we prove under an invertibility condition at infinity that the eta function of the twisted Dirac operator has at most simple poles and is regular at the origin. For hyperbolic manifolds of finite volume, the eta function of the Dirac operator twisted by any homogeneous vector bu…

2009-01-16abs ↗pdf ↗

Road Network Metric Learning improves ETA prediction accuracy by addressing data sparsity.

problem Data sparsity in road network embedding vectors affects ETA prediction accuracy.
method Proposes Road Network Metric Learning (RNML-ETA) framework with an auxiliary metric learning task and triangle loss.
result RNML-ETA outperforms state-of-the-art models and improves prediction accuracy for cold links.