Dark Matter From Spacetime Nonlocality

Abstract

We propose that dark matter is not yet another new particle in nature, but that it is a remnant of quantum gravitational effects on known fields. We arrive at this possibility in an indirect and surprising manner: by considering retarded, nonlocal, and Lorentzian evolution for quantum fields. This is inspired by recent developments in causal set theory, where such an evolution shows up as the continuum limit of scalar field propagation on a background causal set. Concretely, we study the quantum theory of a massless scalar field whose evolution is given not by the the d'Alembertian $\square$, but by an operator $\tilde{\square }$ which is Lorentz invariant, reduces to $\square$ at low energies, and defines an explicitly retarded evolution: $(\tilde{\square }\varphi )(x)$ only depends on $\varphi (y)$, with $y$ is in the causal past of $x$. This modification results in the existence of a continuum of massive particles, in addition to the usual massless ones, in the free theory. When interactions are introduced, these massive or off-shell quanta can be produced by the scattering of massless particles, but once produced, they no longer interact, which makes them a natural candidate for dark matter.

References in corpus (3)

• Feynman Propagator for a Free Scalar Field on a Causal Set
• Generalized Causal Set d'Alembertians
• Nonlocal Scalar Quantum Field Theory from Causal Sets

Cited by in corpus (18)

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• Spectral Dimension from Nonlocal Dynamics on Causal Sets
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• Low energy signatures of nonlocal field theories
• The continuum limit of a 4-dimensional causal set scalar d'Alembertian
• Echoes of Asymptotic Silence in Causal Set Quantum Gravity
• Tests of Quantum Gravity-Induced Non-Locality: Hamiltonian formulation of a non-local harmonic oscillator
• Continuum Modes of Nonlocal Field Theories
• On the Entanglement Entropy of Quantum Fields in Causal Sets
• Transmission of Information in Non-Local Field Theories
• Casimir Effect for Nonlocal Field Theories with Continuum Massive Modes
• Off-shell Dark Matter: A Cosmological relic of Quantum Gravity
• Effects of a scalar scaling field on quantum mechanics
• Universal behaviour of generalized Causal set d'Alembertians in curved spacetime
• Everything You Always Wanted to Know About How Causal Set Theory Can Help with Open Questions in Cosmology, but Were Afraid to Ask
• Observable Effects of Quantum Gravity