Cosmological Landscape From Nothing: Some Like It Hot

Abstract

We suggest a novel picture of the quantum Universe -- its creation is described by the {\em density matrix} defined by the Euclidean path integral. This yields an ensemble of universes -- a cosmological landscape -- in a mixed state which is shown to be dynamically more preferable than the pure quantum state of the Hartle-Hawking type. The latter is dynamically suppressed by the infinitely large positive action of its instanton, generated by the conformal anomaly of quantum fields within the cosmological bootstrap (the self-consistent back reaction of hot matter). This bootstrap suggests a solution to the problem of boundedness of the on-shell cosmological action and eliminates the infrared catastrophe of small cosmological constant in Euclidean quantum gravity. The cosmological landscape turns out to be limited to a bounded range of the cosmological constant ${\Lambda }_{\min }\le \Lambda \le {\Lambda }_{\max }$. The domain $\Lambda <{\Lambda }_{\min }$ is ruled out by the back reaction effect which we analyze by solving effective Euclidean equations of motion. The upper cutoff is enforced by the quantum effects of vacuum energy and the conformal anomaly mediated by a special ghost-avoidance renormalization of the effective action. They establish a new quantum scale ${\Lambda }_{\max }$ which is determined by the coefficient of the topological Gauss-Bonnet term in the conformal anomaly. This scale is realized as the upper bound -- the limiting point of an infinite sequence of garland-type instantons which constitute the full cosmological landscape. The dependence of the cosmological constant range on particle phenomenology suggests a possible dynamical selection mechanism for the landscape of string vacua.

Final version, to appear in JCAP

References in corpus (4)

• Schwinger-Keldysh Propagators from AdS/CFT Correspondence
• The Boundedness of Euclidean Gravity and the Wavefunction of the Universe
• A Note on the Quantum Creation of Universes
• Spontaneous Creation of the Brane World and Direction of the Time Arrow

Cited by in corpus (16)

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• Thermodynamics via Creation from Nothing: Limiting the Cosmological Constant Landscape
• Quantum geometrodynamics: whence, whither?
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• Anomaly Driven Cosmology: Big Boost Scenario and AdS/CFT Correspondence
• Cosmological Landscape and Euclidean Quantum Gravity
• A Wave-function for Stringy Universes
• Arrow of Time in String Theory
• Vacuum energy and spectral function sum rules
• A Renormalization Group Approach to the Cosmological Constant Problem
• Quantum Effective Action in Spacetimes with Branes and Boundaries: Diffeomorphism Invariance
• Spontaneous Creation of the Brane World and Direction of the Time Arrow
• Effective action and heat kernel in a toy model of brane-induced gravity
• Instanton transition in thermal and moduli deformed de Sitter cosmology
• A radiation-like era before inflation
• Unitarity at Infinity and Topological Holography