Nobel laureateSir Anthony J. Leggett, speaking at a public lecture on ‘Why can’t time run backwards?’ explained that the distinction between the future and the past that is observed in our daily life is not readily explained by the most fundamental theories in physics
New insights are required to answer the paradox of time-flow and the past-future distinction, according to Sir Anthony J. Leggett, winner of the Nobel Prize in Physics in 2003 for his pioneering contributions to the theory of superconductors and superfluids.
Prof. Leggett was speaking at a public lecture on ‘Why can’t time run backwards?’ that was jointly organised by the Academy of Physics Teachers — Kerala (APT) and the School of Pure and Applied Physics (SPAP), Mahatma Gandhi University here on Monday.
He elaborated on the physical explanation of time. “We can remember the past and affect the future, and not vice-versa. Likewise, the future and the past have very distinct properties from the human perspective. Yet the basic laws of physics appear to be completely invariant under time reversal. In other wards, they make no distinction between the forward and backward directions of time.
Henceforth, the distinction between the future and the past that is observed in our daily life is not readily explained by the most fundamental theories in physics, such as the Newtonian mechanics, Heisenberg’s quantum mechanics, or Maxwell’s electromagnetism. All of these three fundamental theoretical systems are invariant under time reversal. Any future revisions of fundamental theories, which are inevitable with new discoveries, will probably involve new insights at the issue of time flow and the future versus the past distinction,” he said.
He continued, “While it is possible to remember the past, we cannot foresee the future, and we directly sense or experience the present.”
Thus the present moment of time is a very distinct point on the axis of time, and this point runs from the past to the future. Physics theories do not have any singular ‘present time’. In other words, any point on the axis of time can be assumed to be the present time, concluded Prof. Leggett.
MGU Vice-Chancellor Prof Rajan Gurukkal spoke on the occasion. APT secretary Dr. P.J. Kurian welcomed the gathering. Vice president Dr. G. Geetha presided over the event. Former secretary of APT Dr. Suresh
V. Vettoor proposed a vote of thanks. SPAP Director Prof. N.V. Unnikrishnan and Associate Professor Dr. K. Indulekha were also present during the lecture.
Prof. Leggett, who is on a visit to the Mahatma Gandhi University as part of the Erudite Scholar-in-Residence Programme, also spoke on the topic ‘Impact of Quantum Effects on our classical World View’ during the four-day conference that was organised by the School of Pure and Applied Physics (SPAP).
The conference, which was sponsored by the Tata Institute of Fundamental Research, was attended by Joseph Samuel and Sampoorna Sinha (Raman Research Institute, Bengaluru), S. Sankaranarayanan, Anil Shaji, Sreedhar Dutta (IISER), Prof. N.V. Unnikrishnan, and Prof K. Indulekha (MG University).