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E. D. Stewart

Publications and source records attributed to E. D. Stewart.

6 recordsLinked to original sources
arXiv2001

Inflationary models with a flat potential enforced by non-abelian discrete gauge symmetries

Non-abelian discrete gauge symmetries can provide the inflaton with a flat potential even when one takes into account gravitational strength effects. The discreteness of the symmetries also provide special field values where inflation can end via a hybrid type mechanism. An interesting feature of this method is that it can naturally lead to extremely flat potentials and so, in principle, to inflation at unusually low energy scales. Two examples of effective field theories with this mechanism are given, one with a hybrid exit and one with a mutated hybrid exit. They include an explicit example in which the single field consistency condition is violated.

hep-ph↗
arXiv2000

Non-abelian discrete gauge symmetries and inflation

Obtaining a potential flat enough to provide slow roll inflation is often difficult when gravitational effects are included. Non-abelian discrete gauge symmetries can guarantee the flatness of the inflaton potential in this case, and also provide special field values where inflation can end.

hep-ph↗
arXiv1999

Higher Order Methods for Simulations on Quantum Computers

To efficiently implement many-qubit gates for use in quantum simulations on quantum computers we develop and present methods reexpressing exp[-i (H_1 + H_2 + ...) Δt] as a product of factors exp[-i H_1 Δt], exp[-i H_2 Δt], ... which is accurate to 3rd or 4th order in Δt. The methods we derive are an extended form of symplectic method and can also be used for the integration of classical Hamiltonians on classical computers. We derive both integral and irrational methods, and find the most efficient methods in both cases.

quant-ph↗
arXiv1998

Higher-Order Methods for Quantum Simulations

To efficiently implement many-particle quantum simulations on quantum computers we develop and present methods for inverting the Campbell-Baker-Hausdorff lemma to 3rd and 4th order in the commutator. That is, we reexpress exp{-i(H_1 + H_2 + ...)dt} as a product of factors exp(-i H_1 dt), exp(-i H_2 dt), ... which is accurate to 3rd or 4th order in dt.

quant-ph↗
arXiv1996

Affleck-Dine Baryogenesis after Thermal Inflation

We argue that an extension of the Minimal Supersymmetric Standard Model that gives rise to viable thermal inflation, and so does not suffer from a Polonyi/moduli problem, should contain right-handed neutrinos which acquire their masses due to the vacuum expectation value of the flaton that drives thermal inflation. This strongly disfavours SO(10) Grand Unified Theories. The $μ$-term of the MSSM should also arise due to the vev of the flaton. With the extra assumption that $ m_L^2 - m_{H_u}^2 < 0 $, but of course $ m_L^2 - m_{H_u}^2 + |μ|^2 > 0 $, we show that a complicated Affleck-Dine type of baryogenesis employing an $LH_u$ $D$-flat direction can naturally generate the baryon asymmetry of the Universe.

hep-ph↗