
Theoretical and Observational Implications of Planck’s Constant as a Running Fine
Structure Constant
Ahmed Farag Ali ∇△ ,∗Jonas Mureika□,⃝,†Elias C. Vagenas⊕,‡and Ibrahim Elmashad △ §
△Department of Physics, Benha University, Benha 13518, Egypt
∇Essex County College, 303 University Ave, Newark, NJ, USA 07102
□Department of Physics, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA, USA 90045
⃝Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, USA 93106 and
⊕Department of Physics, College of Science, Kuwait University,
Sabah Al Salem University City, P.O. Box 2544, Safat 1320, Kuwait
This letter explores how a reinterpretation of the generalized uncertainty principle as an effective
variation of Planck’s constant provides a physical explanation for a number of fundamental quantities
and couplings. In this context, a running fine structure constant is naturally emergent and the
cosmological constant problem is solved, yielding a novel connection between gravitation and
quantum field theories. The model could potentially clarify the recent experimental observations
by the DESI Collaboration that could imply a fading of dark energy over time. When applied to
quantum systems and their characteristic length scales, a simple geometric relationship between
energy and entropy is disclosed. Lastly, a mass-radius relation for both quantum and classical
systems reveals a phase transition-like behaviour similar to thermodynamical systems, which we
speculate to be a consequence of topological defects in the universe.
I. INTRODUCTION
Various approaches to quantum gravity such as string
theory, loop quantum gravity, and quantum geometry
suggest a generalized form of the uncertainty principle
(GUP) that implies the existence of a minimal
measurable length. Several forms of the GUP that
include non-relativistic and relativistic forms have been
proposed [1–8], which can be collectively written in the
form :
∆x∆p≥
ℏ
2f(p, x).(1)
Phenomenological and experimental implications of the
GUP have been investigated in low and high-energy
regimes. These include atomic systems [9, 10], quantum
optical systems [11], gravitational bar detectors [12],
gravitational decoherence [13, 14], composite particles
[15], astrophysical systems [16], condensed matter
systems [17], and macroscopic harmonic oscillators
[18]. Reviews of the GUP, its phenomenology, and its
experimental implications can be found in Refs. [19, 20].
Recently, we proposed a reinterpretation of the GUP
using an effective Planck constant [21] by absorbing
the additional momentum uncertainty dependence, ℏ′=
ℏf(p, x). This implies a generic GUP of the form:
∆x∆p≥
ℏ′
2.(2)
∗email: aali29@essex.edu ; ahmed.ali@fsc.bu.edu.eg
†email: jmureika@lmu.edu
‡email: elias.vagenas@ku.edu.kw
§email: ibrahim.elmashad@fsc.bu.edu.eg
Previously, in Ref. [22], the GUP was conceptualized as
an effective variation of the Planck constant by isolating
an invariant phase space with minimal length in the
context of Liouville’s theorem. Planck constant was
proposed to vary with momentum in Ref. [23], where
the authors introduced a generalized picture of the
de Broglie relation and derived a form of generalized
uncertainty principle which is similar to the one obtained
in string theory. In Ref. [21], we argued that the charge
radii of hadrons/nuclei along with their corresponding
masses support the existence of an effective variation
of ℏthat suggests a universality of a minimal length
in the associated scattering process. We suggested
a relation that simulates the fundamental connection
between nature constants (ℓPMPc=ℏ,) by replacing
the Planck length ℓPby the charge radius (r) and the
Planck mass MPby the mass of the hadron/nuclei (m).
This relation reads :
r m c =ℏ′,(3)
where ris the charge radius of the particle, mis the
particle’s relativistic mass 1,cis the speed of light and
ℏ′is the effective Planck constant. Here, cis a constant to
maintain consistency with the theory of relativity. It was
further shown in [21] that applying Eq. (3) to a variety of
hadronic particles, as well as to larger nuclei, a clear trend
in the effective ℏ′was apparent. It was suggested this
effective variation of Planck constant might be related to
the timeless state of the universe [24]. In this letter,
we propose a connection between Eq. (3) and the
universal Bekenstein bound [25] (Sec. II). Furthermore,
1The particle’s relativistic mass mis given by m=
m0/p1−v2/c2, where m0is the rest mass and vis the particle’s
speed.
arXiv:2210.06262v3 [physics.gen-ph] 6 Jun 2024