Related papers: Empirical constraints on vacuum decay in the strin…
We consider examples of long-lived false vacua in quantum field theory that arise from so-called `universes'. These false vacua are protected by a $(d-1)$-form global symmetry, where $d$ is the dimension of spacetime. The lifetimes of the…
The transition from a false vacuum to the true vacuum is a real-time phenomenon of interest in many contexts. It represents a special challenge for strongly interacting non-Abelian gauge theories because standard spacetime lattices…
While the number of metastable landscape vacua in string theory is vast, the number of supermoduli vacua which lead to distinct low energy physics is even larger, perhaps infinitely so. From the anthropic perspective it is therefore…
Changing the dimensionality of the space-time at the smallest and largest distances has manifold theoretical advantages. If the space is lower dimensional in the high energy regime, then there are no ultraviolet divergencies in field…
After reviewing the cosmological constant problem - why is Lambda not huge? - I outline the two basic approaches that had emerged by the late 1980s, and note that each made a clear prediction. Precision cosmological experiments now indicate…
In this paper we generalize the black hole bound of arXiv:0706.2050 to de Sitter spaces, and apply it to various vacua in the landscape, with a special emphasis on slow-roll inflationary vacua. Non-trivial constraints on the lifetime and…
If there is a shortest length in nature, for example at the Planck scale of 10^-35m, then the cosmic expansion should continually create new comoving modes. A priori, each of the new modes comes with its own vacuum energy, which could…
It has been claimed that the string landscape predicts an open universe, with negative curvature. The prediction is a consequence of a large number of metastable string vacua, and the properties of the Coleman--De Luccia instanton which…
We assess how physically realistic the ''simulation hypothesis'' for this Universe is, based on physical constraints arising from the link between information and energy, and on known astrophysical constraints. We investigate three cases:…
We investigate some classical aspects of fundamental strings via numerical experiments. In particular, we study the thermodynamics of a string network within a toroidal universe, as a function of string energy density and space…
[Talk presented at the International Seminar Quarks `92, Zvenigorod, Russia, May 11-17, 1992.] The electroweak vacuum need not be absolutely stable. For certain top and Higgs masses in the Minimal Standard Model, it is instead metastable…
Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search…
Recent LHC results concerning the mass of the Higgs boson indicate that the vacuum in our Universe may be unstable. We analyze properties of unstable vacuum states from the point of view of the quantum theory of unstable states. From the…
Some time ago we have suggested that positive vacuum energy exhibits a finite quantum break time, which can be a signal that a positive cosmological constant is inconsistent. From the requirement that Universe never undergoes through…
In this paper, we evaluate the lifetime of the light stringy states that emerge in intersecting D-brane realisations of the Standard Model. For concreteness, we focus on a light massive scalar decaying into two massless fermions. Given the…
Quantum Space Time may be characterized by a plethora of novel phenomena, such as Lorentz violations and non-trivial refractive indices, stochastic metric fluctuation effects leading to decoherence of quantum matter and non-commutativity of…
We consider the decay of cosmic strings that are trapped in the false vacuum in a theory of scalar electrodynamics in 3+1 dimensions. We restrict our analysis to the case of thin-walled cosmic strings which occur when large magnetic flux…
The cosmological observations provide a strong evidence that there is a positive cosmological constant in our universe and thus the spacetime is asymptotical de Sitter space. The conjecture of gravity as the weakest force in the…
We use the recently modified Friedmann equations obtained from string T-duality effects that encode the zero-point length (Phys. Lett. B 836 (2023), 137621) to study the phase space analyses of a bouncing early universe. An important…
We revisit the neutron lifetime puzzle, a discrepancy between beam and bottle measurements of the weak neutron decay. Since both types of measurements are realized at different times after the nuclear production of free neutrons, we argue…