Research papers
1987 · Physical Review Letters · 13,997 citations
It has been recognized for some time that the spontaneous emission by atoms is not necessarily a fixed and immutable property of the coupling between matter and space, but that it can be controlled by modification of the properties of the radiation field. This is equally true in the solid state, where spontaneous emission plays a fundamental role in limiting the performance of semiconductor lasers, heterojunction bipolar transistors, and solar cells. If a three-dimensionally periodic dielectric structure has an electromagnetic band gap which overlaps the electronic band edge, then spontaneous emission can be rigorously forbidden.
2009 · Classical and Quantum Gravity · 1,659 citations
These notes are loosely based on lectures given at the CERN Winter School on Supergravity, Strings and Gauge theories, February 2009, and at the IPM String School in Tehran, April 2009. I have focused on a few concrete topics and also on addressing questions that have arisen repeatedly. Background condensed matter physics material is included as motivation and easy reference for the high energy physics community. The discussion of holographic techniques progresses from equilibrium, to transport and to superconductivity.
2026 · Zenodo (CERN European Organization for Nuclear Research)
The Gamma function diverges at negative integer and half-integer arguments, posing a fundamental obstacle for both perturbative and non-perturbative theories. Analytic continuation, while guaranteeing uniqueness, does not preserve the Euler integral representation in the left half-plane, as noted by Hardy and Titchmarsh. We present a continuous regularization technique - the Dual Architecture - that addresses this limitation through a complementary function with directional vector opposite to that of the Gamma function. The phase function is uniquely determined by the boundary conditions and , and its periodicity is established by Lemma 2.1. The regularized function for is finite by construction at all points where the classical Gamma function diverges, unifying regulation and subtraction within a single definition. We demonstrate the physical applicability of the technique across six systems: the cosmological constant, the Higgs boson mass, the strong CP problem, the Casimir effect, dimensional regularization in , and a divergent Gaussian integral. In each case, the algebraic development is presented in full, yielding analytical results consistent with experimental values. The technique offers a unified framework for treating Gamma-function divergences across perturbative and non-perturbative regimes. Keywords: Continuous regularization, Gamma function, uniqueness theorem, Casimir effect, Standard Model.
2026 · Zenodo (CERN European Organization for Nuclear Research)
The Gamma function diverges at negative integer and half-integer arguments, posing a fundamental obstacle for both perturbative and non-perturbative theories. Analytic continuation, while guaranteeing uniqueness, does not preserve the Euler integral representation in the left half-plane, as noted by Hardy and Titchmarsh. We present a continuous regularization technique - the Dual Architecture - that addresses this limitation through a complementary function with directional vector opposite to that of the Gamma function. The phase function is uniquely determined by the boundary conditions and , and its periodicity is established by Lemma 2.1. The regularized function for is finite by construction at all points where the classical Gamma function diverges, unifying regulation and subtraction within a single definition. We demonstrate the physical applicability of the technique across six systems: the cosmological constant, the Higgs boson mass, the strong CP problem, the Casimir effect, dimensional regularization in , and a divergent Gaussian integral. In each case, the algebraic development is presented in full, yielding analytical results consistent with experimental values. The technique offers a unified framework for treating Gamma-function divergences across perturbative and non-perturbative regimes. Keywords: Continuous regularization, Gamma function, uniqueness theorem, Casimir effect, Standard Model.