Eur. Phys. J. C (2014) 74:2880
DOI 10.1140/epjc/s10052-014-2880-9
Regular Article - Theoretical Physics
Topological vertex, string amplitudes and spectral functions
of hyperbolic geometry
M. E. X. Guimarães
1,a
,R.M.Luna
2,b
,T.O.Rosa
1,c
1
Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, CEP 24210-346, Niterói, RJ, Brazil
2
Departamento de Física, Universidade Estadual de Londrina, Caixa Postal 6001, Londrina, Paraná, Brazil
Received: 28 March 2014 / Accepted: 28 April 2014 / Published online: 20 May 2014
© T he Author(s) 2014. This article is published with open access at Springerlink.com
Abstract We discuss the homological aspects of the con-
nection between quantum string generating function and the
formal power series associated to the dimensions of chains
and homologies of suitable Lie algebras. Our analysis can
be considered as a new straightforward application of the
machinery of modular forms and spectral functions (with
values in the congruence subgroup of SL(2, Z)) to the parti-
tion functions of Lagrangian branes, r efined vertex and open
string partition functions, represented by means of formal
power series that encode Lie algebra properties. The com-
mon feature in our examples lies in the modular properties
of the characters of certain representations of the pertinent
affine Lie algebras and in the role of Selberg-type spectral
functions of a hyperbolic three-geometry associated with q-
series in the computation of the string amplitudes.
1 Introduction
In this work, we deal with some applications of the modular
forms ( and spectral functions related to the congruence sub-
group of SL(2, Z)) to topological vertex and string generat-
ing functions. For mathematicians topological vertices (and
their respective string generating functions) may be associ-
ated to new mathematical invariants for spaces, while, for
physicists, they are related to quantum string partition func-
tions.
Having made these general remarks, let us now explain the
connection between the specific contents of the various sec-
tions in more detail. In Sect. 2 we will explore a remarkable
connection between Poincaré polynomials (generating func-
tions) and formal power s eries associated with dimensions of
chains and homologies of Lie algebras (Euler–Poincaré for-
a
e-mail: emilia@if.uff.br
b
e-mail: luna@uel.br
c
e-mail: t18rosa@if.uff.br
mula). From a concrete point of view this paper consists of
applications of spectral functions to quantum string partition
functions connected to suitable Lie algebras.
We show that the Poincaré polynomials (Sect. 3) and the
associated topological vertex and string amplitude can be
converted into product expressions which inherit cohomo-
logical properties (in the sense of characteristic classes of
foliations [1]) of appropriate polygraded Lie algebras.
The final result for a single Lagrangian brane, stack of
branes (Sect. 4), refined vertex, and the partition functions for
the case of Calabi–Yau threefolds O(−1) ⊕ O(−1) → P
1
and O(0) ⊕ O(−2) → P
1
(Sect. 5) is written in terms of
spectral functions of the hyperbolic three-geometry associ-
ated with q-series.
2 Graded algebras and spectral functions of hyperbolic
geometry
Before considering topological vertex and string amplitudes
we would like to spend some time on the relation between
formal power q-series and homologies of Lie algebras. We
would like to show how combinatorial identities could be
derived from the initial complex of (graded) Lie algebras.
Our interest is the Euler–Poincaré formula associated with a
complex consisting of linear spaces. The relations between
Lie algebras and combinatorial identities was first discov-
ered by Macdonald; the Euler–Poincaré formula is useful for
combinatorial identities known as Macdonald identities. The
Macdonald identities are related to Lie algebras in one way
or another and can be associated with generating functions
in quantum theory.
Let g be a Lie algebra, and assume that it has a grad-
ing, i.e. g is a direct sum of homogeneous components g
(λ)
,
where the λ’s are elements of an abelian group, [g
(λ)
, g
(μ)
]⊂
g
(λ+μ)
. Let us consider a module k over g,org-module,
which is a left module over the universal enveloping algebra
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