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We propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous $ U(1)_{X} $ group. Anomaly…
In a simple reanalysis of the KKLMMT scenario, we argue that the slow roll condition in the D3-anti-D3-brane inflationary scenario in superstring theory requires no more than a moderate tuning. The cosmic string tension is very sensitive to…
The magnetic monopole of a dark sector has been advocated as an appealing dark matter candidate. We revisit the computation of the monopole abundance $\Omega_M$, generated by a thermal phase transition in the minimal 't Hooft-Polyakov…
A brief review is given of dark matter in SUGRA, strings and branes. For SUGRA models the implications of Yukawa coupling unification on dark matter are discussed in the light of $g-2$ and $b\to s\gamma$ constraints. A brief discussion is…
Magnetic monopoles are an inevitable feature of post-inflation symmetry-breaking phase transitions in grand unified theories. Analytic estimates of their density indicate that they are compatible with standard cosmology only if their mass…
Considerable and ongoing effort is made to identify promising scalar field candidates in string theory to drive a cosmological period of inflation. At stake is the possibility that fundamental string parameters could be encoded in…
We show that the naive application of the Kibble mechanism seriously underestimates the initial density of cosmic superstrings that can be formed during the annihilation of D-branes in the early universe, as in models of brane-antibrane…
Spontaneous symmetry breaking in grand unified theories is thought to have produced an exceedingly large number of magnetic monopoles in the early Universe. In the absence of suppression or annihilation, these very massive particles should…
Astrophysical observations provide the best evidence of physics beyond the particle physicists' standard model. Over the past decade, the case has solidified for inflation, dark energy, dark matter and massive neutrinos. In this report we…
Dark photons are a theorized massive spin-1 particle which can be produced via various mechanisms, including cosmological gravitational particle production (GPP) in the early universe. In this work, we extend previous results for GPP of…
We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation.…
We exploit the techniques of dynamical systems to study the cosmological evolution of cosmic fundamental strings and effective strings arising from branes wrapped on internal cycles. We also include the whole potential of the volume modulus…
Recently it was observed that the hyperbolic compactification of M/string theory related to S-branes may lead to a transient period of acceleration of the universe. We study time evolution of the corresponding effective 4d cosmological…
The prediction of a phase of inflation whose number of e-folds is constrained is an important feature of loop quantum cosmology. This work aims at giving some elementary clarifications on the role of the different hypotheses leading to this…
In this talk, based on \cite{Kane:2001rb}, we emphasise that intermediate scale supersymmetric inflation models are particularly attractive since inflation, baryogenesis and the relic abundance of cold dark matter (CDM) are all related by a…
The monopole mass is revealed to be considerably modified in the thick braneworld paradigm, and depends on the position of the monopole in the brane as well. Accordingly, the monopole radius continuously increases, leading to an…
We investigate the embedding of brane inflation into stable compactifications of string theory. At first sight a warped compactification geometry seems to produce a naturally flat inflaton potential, evading one well-known difficulty of…
The early cosmic inflation, when taken along with the recent observations that the universe is currently dominated by a low density vacuum energy, leads to at least two potential problems which modern cosmology must address. First, there is…
This paper consider an universe dominated by baryonic matter, radiation and a nonminimally coupled massive scalar field under the action of a symmetry breaking potential. Inflation occurs naturally with appropriated slow-roll values. The…
Cosmological constraints on moduli, whose coupling to matter is stronger than Planck mass suppressed coupling, are derived. In particular, moduli are considered to be produced by oscillating loops of cosmic strings and constraints are…