62
T. K. Mathew
2 A Very Brief History of Association Between Prof. Babu
Joseph and Prof. Sabir
Prof. Sabir joined with Prof. Babu Joseph for Ph.D. in the year 1974. They together
started working on field theory, a pioneer area in theoretical physics at that time.
After Ph.D., Prof. Sabir joined the Department of Physics as a faculty in 1979 where
his guru, Prof. Babu Joseph was a senior professor. This became the second spell
of the continuation of their long-term association, which culminated into the fruitful
research in many fields like field theory, non-linear dynamics, gravity, etc. Prof.
Babu Joseph (KBJ) later became the Head of the same Department and then became
the Vice-Chancellor of CUSAT. Prof. Sabir (MS) retired from service in the year
2011 and then continued as an Emeritus Professor there until his death on October
2019. Their association resulted into some remarkable publications in the field of
field theory, non-linear dynamics and gravity. Among these, we will concentrate on
gravity which acquired much appreciation from Theoretical Physicist community
during that time.
3 On Gravity
As noted earlier the important contribution of KBJ and MS in gravity is their pioneer
work on the reformulation of Einstein’s gravity as flat space gauge theory. This work
has been published as a paper in the reputed journal, Modern Physics Letters A in the
year 1988. It was an important contribution towards the dream of creating a quantum
theory of gravity.
Einstein’s theory of gravity is a revolution in understanding gravity. Even though
Newton’s theory of gravity was very successful in predicting the Kepler’s planetary
laws, it fails in explaining the perihelion shift of planet Mercury accurately and also
in understanding the effect of gravity on light. Around 1915, Einstein reformulated
gravity in a completely new framework, in which the gravity is explained as a geometrical theory of space–time. The all time new idea was that matter can influence
the geometry of the space–time around it and gravity is nothing but this effect of
matter on space–time. Hence a correct equation of gravity is a relation between the
modified geometry of the space–time and the energy/matter present in the given location. In the absence of gravity, the geometry of the space–time is similar to Euclidean
and is often called as flat geometry. But, in the presence of matter, the geometry of
the surrounding space–time will become non-Euclidian or say Riemannian and is
referred to as curved geometry. The curvature of the space–time is represented by
Einstein tensor, G ab which is then equated to the matter and energy represented by
a second rank tensor, T ab . The new law of gravity is then stated as
G ab = κ T ab ,
(1)
T. K. Mathew
2 A Very Brief History of Association Between Prof. Babu
Joseph and Prof. Sabir
Prof. Sabir joined with Prof. Babu Joseph for Ph.D. in the year 1974. They together
started working on field theory, a pioneer area in theoretical physics at that time.
After Ph.D., Prof. Sabir joined the Department of Physics as a faculty in 1979 where
his guru, Prof. Babu Joseph was a senior professor. This became the second spell
of the continuation of their long-term association, which culminated into the fruitful
research in many fields like field theory, non-linear dynamics, gravity, etc. Prof.
Babu Joseph (KBJ) later became the Head of the same Department and then became
the Vice-Chancellor of CUSAT. Prof. Sabir (MS) retired from service in the year
2011 and then continued as an Emeritus Professor there until his death on October
2019. Their association resulted into some remarkable publications in the field of
field theory, non-linear dynamics and gravity. Among these, we will concentrate on
gravity which acquired much appreciation from Theoretical Physicist community
during that time.
3 On Gravity
As noted earlier the important contribution of KBJ and MS in gravity is their pioneer
work on the reformulation of Einstein’s gravity as flat space gauge theory. This work
has been published as a paper in the reputed journal, Modern Physics Letters A in the
year 1988. It was an important contribution towards the dream of creating a quantum
theory of gravity.
Einstein’s theory of gravity is a revolution in understanding gravity. Even though
Newton’s theory of gravity was very successful in predicting the Kepler’s planetary
laws, it fails in explaining the perihelion shift of planet Mercury accurately and also
in understanding the effect of gravity on light. Around 1915, Einstein reformulated
gravity in a completely new framework, in which the gravity is explained as a geometrical theory of space–time. The all time new idea was that matter can influence
the geometry of the space–time around it and gravity is nothing but this effect of
matter on space–time. Hence a correct equation of gravity is a relation between the
modified geometry of the space–time and the energy/matter present in the given location. In the absence of gravity, the geometry of the space–time is similar to Euclidean
and is often called as flat geometry. But, in the presence of matter, the geometry of
the surrounding space–time will become non-Euclidian or say Riemannian and is
referred to as curved geometry. The curvature of the space–time is represented by
Einstein tensor, G ab which is then equated to the matter and energy represented by
a second rank tensor, T ab . The new law of gravity is then stated as
G ab = κ T ab ,
(1)