VIBHUTI BHUSHAN JHAPHYSICAL SCIENCES

FUNDAMENTAL FORCES

FORCES :

FOUR FORCES :

1)ELECTROMAGNETIC FORCE 2)WEAK FORCE 3)STRONG FORCE 4)GRAVITATIONAL FORCE

FORCE CARRIERS:

ELECTROMAGNETIC FORCE: PHOTONS

STRONG FORCE: GLUONS

WEAK FORCE : BOSONS

GRAVITATIONAL FORCE: ????

STRONG FORCE :strongest of all

MAGNITUDE: 100X >EM FORCE

RANGE :1 TO 3 fm

NUCLEAR FORCE : BINDS PROTONS NEUTRONS.

FORCE CARRIERS: GLUONS

STRONG FORCE :CONTD…

PROTONS AND NEUTRONS: MADE OF QUARKSProtons :2 up & 1 downNeutrons:2 down & 1 up

Up quarks :2/3+Down quarks:1/3-Originally called T & B quarks.

Cont…

Where are the gluons??Gluons hold the quarks…and thus hadrons are formed.

Gluons =force carriers Force carried through color charge!!3 color gluons: RGB(QCD)

RESIDUAL STRONG FORCE:

Diminishes rapidly with distance.

 force between the "colorless" hadrons.

Action described by YUKAWA POTENTIAL.

WEAK FORCE:

CARRIERS :W AND Z BOSONS.

 FERMIONS interact through the weak interaction.

RADIOACTIVE DECAY.

QUARKS COME IN FLAVOURS.

BREAKS PARITY AND CP SYMMETRY.

PROPERTIES:

CHANGES FLAVOUR OF QUARKS.

VIOLATES SYMMETRY.

PROPAGATED BY CARRIERS HAVING SIGNIFICANT MASS EXPLAINED BY HIGGS MECHANISM.

CONT…

SHORT LIVED CHARGE CARRIERS.

DOESNOT PRODUCE BOUND STATES.

BETA DECAY

ELECTROWEAK THEORY

ELECTROMAGNETIC FORCE:

FORCE CARRIERS: PHOTONS

Electric fields and magnetic fields.

Friction and all other practical forces derived from electromagnetic theory.

cont..

Violates Galilean invariance.

Culminated in the establishment of relativity.

Abraham –lorentz force:

Recoil force on an accelerating charge particle.

F directly proportional to (charge * jerk).

Solution violates causality.

Ex..pre acceleration

Futuristic signals:

Wheeler –Feynman absorber theory

Solutions derived from assumption of time reversal symmetry.

Concept of retarded and advanced solutions.

 Charged particles are considered as both emitters and absorbers.

All the charged particle in the universe are considered.

We should have some maths !!!

The resulting field is

But the assumption is that the free field must be zer0.

Last but not the least ,GRAVITY:

FORCE CARRIERS:??????

WHAT IS GRAVITY?

MEWTONIAN GRAVITATION AND IT’S PROBLEM:

ACTION AT A DISTANCE .

INSTANTANEOUS TRANSMISSION OF FORCE

A WAY TO GENERAL RELATIVITY:

GRAVITY IS A FICTITIOUS FORCE,VIRTUE OF THE CURVED SPACE TIME.

NON EUCLIDEAN GEOMETRY

GEODESICS

TESTS OF GR:

PRECESSION OF THE PERIHELION OF MERCURY

GRAVITATIONAL LENSING

RED SHIFT

PRECESSION OF PERIHELION OF MERCURY:

GRAVITATIONAL LENSING(VERIFIED BY SIR EDDINGTON)

GRAVITONS:

HYPOTHETICAL PARTICLES.

MASSLESS SPIN 2 BOSON .

DETECTION IS PHYSICALLY IMPOSSIBLE WITH PRESENT STATE OF TECHNOLOGY.

WE SHOULD DETECT A SPIN 2 BOSON WHICH IS MASSLESS.

PROBLEMS WHEN EINSTEIN AND DIRAC MEET:

INFINITES ARE INFINITE.

RENORMALISATION LEADS TO PROBLEMS.

PROBABILITY GIVES NONSENSE ANSWERS

QUANTUM MECHANICS AND GENERAL RELATIVITY ,, ARE LIKE SIBBAL AND MANMOHAN IN SAME GLASS.

WHATS THE SOLUTION??A PATH TO UNIFICATION:

SO HOW TO UNIFY ALL THE FORCES INTO A SINGLE ONE

WHAT IS THE THEORY THAT UNIFIES ALL?

A LOOK INTO SOME THEORIES: 1)QUANTUM FIELD THEORY 2)QUANTUM LOOP GRAVITY 3)STRING THEORY 4)THEORY OF EVERYTHING 5)GRAND UNIFIED THEORY

QUANTUM LOOP GRAVITY:

Space is quantised!!(and that too discrete)

Space can be viewed as a fabric woven of finite loops.

Planck’s length is its domain.

spin foam :

CONTD….

LOOP QUANTUM COSMOLOGY:BIG BANG OR BIG BOUNCE:TIME IN QUANTUM GRAVITY

( Spacetime is no longer an absolute background object, but is dynamical. Gravity is a manifestation of spacetime geometry.)

STRING THEORY:

CONTD…

Theory of everything:

It is an attempt of merging all the forces.

Quantum mechanics applied to general relativity leads to disaster.

It should also answer dark energy , inflationary force concepts too.

Arguments against unified theories.

GODEL’S INCOMPLETENESS THEOREM:

“ any formal theory expressive enough for elementary arithmetical facts to be expressed and strong enough for them to be proved is either inconsistent (both a statement and its denial can be derived from its axioms) or incomplete, in the sense that there is a true statement about natural numbers that can't be derived in the formal theory.”

VEDIC PHILOSOPHY OF UNIFICATION:

REFERENCES:

WIKIPEDIAEINSTEIN AND EDDINGTONWITTENGRIFFITHSGREINERLEONARD SUSSKINDRESONANCE

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