By Ravin Sharma,EEE 4th Year
An electron is a subatomic negatively charged elementary particle having a charge of , a mass of and a spin of ½. But have you ever wondered why each electron has the same properties? Theoretical Physicist, John Archibald Wheeler presented a brilliant idea on this question to the Noble Laureate in Physics, Richard Feynman during a telephone conversation:
…I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, “Feynman, I know why all electrons have the same charge and the same mass” “Why?” “Because, they are all the same electron!”
- Richard Feynman, Noble Lecture, 11 December, 1965.
Albert Einstein in his theory of relativity suggested that time is the fourth dimension and one usually assumes that an electron in space-time should always move up in the direction of time. But what if it could travel backwards and forwards in time again and again such that trajectories of an electron seem like a knot or loop in space-time? These trajectories are now called Feynman Diagrams. Thus we see number of negatively and positively charged particles at the same time but in fact they are all the same electronwhich has travelled back and forth in time and the positively charged particles are positrons (electrons having positive charge and a form of antimatter).
Feynman observed that when a Gamma ray photon hits matter, an electron is emitted in one direction and a positron is emitted in the other. The positron then collides with another electron and some energy is released and both the particles are annihilated. Hence it was concluded that the electron emitted by the first collision replaces the other electron. Feynman suggested that both the electrons exist at the same time but are in fact the same particle, and the positron travelled back in time. Thus initially there was the second electron that collided with positron and the positron travelled back in time and became the electron that was emitted during the gamma ray collision with matter. Thus one would see three particles (two negatively charged and one positively charged particle) at the same time which are in fact a single electron. This theory also predicts that universe must be made of equal amount of matter and antimatter. However this theory encountered a small problem, that there cannot be as many positrons as there are electrons. But there are many such particles in vacuum which come into existence and disappear after collision with their antimatter to release some energy (or photons) in a similar manner. This energy is also known as Vacuum Energy or Dark Energy.
…I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, “Feynman, I know why all electrons have the same charge and the same mass” “Why?” “Because, they are all the same electron!”
- Richard Feynman, Noble Lecture, 11 December, 1965.
Albert Einstein in his theory of relativity suggested that time is the fourth dimension and one usually assumes that an electron in space-time should always move up in the direction of time. But what if it could travel backwards and forwards in time again and again such that trajectories of an electron seem like a knot or loop in space-time? These trajectories are now called Feynman Diagrams. Thus we see number of negatively and positively charged particles at the same time but in fact they are all the same electronwhich has travelled back and forth in time and the positively charged particles are positrons (electrons having positive charge and a form of antimatter).
Feynman observed that when a Gamma ray photon hits matter, an electron is emitted in one direction and a positron is emitted in the other. The positron then collides with another electron and some energy is released and both the particles are annihilated. Hence it was concluded that the electron emitted by the first collision replaces the other electron. Feynman suggested that both the electrons exist at the same time but are in fact the same particle, and the positron travelled back in time. Thus initially there was the second electron that collided with positron and the positron travelled back in time and became the electron that was emitted during the gamma ray collision with matter. Thus one would see three particles (two negatively charged and one positively charged particle) at the same time which are in fact a single electron. This theory also predicts that universe must be made of equal amount of matter and antimatter. However this theory encountered a small problem, that there cannot be as many positrons as there are electrons. But there are many such particles in vacuum which come into existence and disappear after collision with their antimatter to release some energy (or photons) in a similar manner. This energy is also known as Vacuum Energy or Dark Energy.