India has always been enamoured with the sciences — children
who fail to secure top marks in mathematics or physics are often considered
“average” students. That said this almost manic preponderance has its upsides
as well.

For long, the country has produced some of the top
scientists and innovators in the world but given India’s education,
particularly research climate, one would have imagined that the brain drain
from these parts to nations abroad has become irreversible. That contention,
though, seems a long shot as several Indian institutes, specifically those
catering to the sciences, boast research scholars of the highest calibre.

And one of the most popular branches of physics for budding
scientists or even otherwise, globally as well as India, is quantum mechanics.
It can be defined, in simplistic terms, as the mathematical study of the motion
and interaction of sub-atomic particles like photons and electrons among
others. The subject calls for clear understanding of complex concepts that
serve to augment our understanding of nature.

In the course of a conversation, Sunil Mukhi, professor and
chair, department of physics, Indian Institute of Science Education and
Research, Pune, spoke about what it takes to become a research scholar in
quantum mechanics, places where cutting-edge research is being conducted across
the country and his experience of teaching the subject for several years now.
Excerpts:

How is the study of quantum mechanics different from other
branches of physics?

Quantum mechanics is responsible for most, though not all,
phenomena that are considered worthy of scientific investigation today (the
exceptions are the physics of biological systems, which typically does not need
quantum mechanics to understand and the physics of certain astronomical
phenomena). The principles are rather counter-intuitive, requiring us to accept
wave-particle duality, inherent uncertainties in measurements and strange
phenomena like superconductivity among other things.

At the same time, the equations are very precise and so are
the experiments. Therefore quantum mechanics provides a world where theory and
experiment can be matched with each other, even though neither of these matches
in a simple way with our everyday experience.

What are the key concepts that students need to master
before venturing into research in the subject?

Research on quantum mechanics roughly covers three different
frontiers.

One is the study of elementary particles and fundamental
interactions. Here one has to use relativistic quantum theory, much more
complex than the non-relativistic version. The modern formulation of
relativistic quantum theory is “quantum field theory”. Moreover, to understand
gravitational phenomena one needs a quantum theory of gravity. One approach to
this is called string theory but there are some other possible approaches. In
short, this frontier requires the understanding of at least quantum field
theory and possibly, gravity and string theory.

The second frontier is the study of condensed matter systems
and emergent phenomena. Here one has to understand many-body quantum physics
because there are literally billions of particles interacting with each other.
The quantum theory of many-body systems (both weakly interacting and strongly
correlated kinds) is much more complex than the one-particle quantum mechanics
that students learn at first.

The third frontier occurs in the study of atoms at very low
temperature. Although the basic laws of quantum mechanics are quite
well-understood for these systems, one focuses on fascinating phenomena like
quantum entanglement and quantum information, which provide a deeper
understanding as well as possible applications. These are hot topics of both
theoretical and experimental research today.

One fascinating thing about physics is that research in any
one of the areas described above can illuminate the study of the other two as
well. So, I feel that students should specialise in one of them but also
acquire a general knowledge of the other two.

In India, we have a weakness for over-specialisation, while
many of the new results coming from abroad are arising because of
cross-fertilisation across different areas.

Please mention some of the areas of quantum mechanics and
institutes where cutting-edge research is being conducted across India.

Active areas of research in physics where quantum mechanics
is used are elementary particle physics, gravitation, condensed matter physics,
atomic and molecular physics, quantum optics and photonics.

The Tata Institute of Fundamental Research, Mumbai; the
Indian Institute of Science; Bangalore; the Indian Institute of Science
Education and Research, Pune, together with the other IISERs (Trivandrum,
Mohali, Kolkata and Bhopal) as well as the IITs and some universities in India
have cutting-edge programmes in one or more of these fields.

If a student wishes not to go into research after completing
a Master’s in quantum mechanics, which are the sectors he/she can explore for
landing a job?

There are industries where some aspect of quantum mechanics
is directly used, — for example device fabrication, nano technology et al. I
understand that many finance companies are interested in people with training
in theoretical physics. Having studied quantum mechanics, a student would have
the ability to juggle abstract concepts, physical intuition and mathematical
rigour.

On an average, how much can a research scholar or professor
in the subject earn in the IITs or elsewhere in India?

As I understand, the starting salary for an assistant
professor (junior-most faculty position) is about Rs 75,000 (consolidated) per
month. It goes to nearly double that at senior levels. The amounts will also go
up with the next Pay Commission.

On a personal note, how has your experience been when it
comes to teaching the subject? Are more students interested in it than before?

Yes, I find it amazing how much Indian students are
interested in quantum theory and how much intelligence and energy they bring to
it.

What makes this profession such a joy is that whatever you
think you know there are always brilliant students who will challenge it and
take you out of your comfort zone. The result is that you keep learning more,
and that is a real pleasure.

By Abhiraj Ganguli