# QUANTUM GRAVITY (UNSOLVED FORCE)

# Currently gravity is based on “Albert Einstein’s general theory of relativity”  which is formulated with the Classical Physics.

# Quantum Gravity is generally used to describe the gravitational field and unite all forces in a single force.

# In Quantum Theory, it gives rise to a String Theory.

# String Theory however on the other side try to unify gravity with other fundamental forces such as quantum loop.

GUT (Grand Unified Theory)

# In above diagram, various fields have their won meaning but when come to end “Quantum Gravity” stuck the mind of everyone.

# Standard Model of Physics yet is unable to find the GUT ( Grand Unified Theory) and still facing a problem of “Gravitons” (that is 2-spin massless particles).

# In Kaluza-Klein Theory, five dimensional theory combined with the gravitation and electromagnetism as it generally appears in String Theory.

# There are many ways to define Quantum Gravity such as ‘”Quantum Loop Gravity”, “Time”, String Theory” , Nonrenormalizability of Gravity and many others ways.

# Quantum Gravity is no the end of the ultimate reality as this is still a smaller beginning.

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# STRINGS OF THE UNIVERSE

# String Theory is consider to be a point like particles which are replaced by one dimensional objects.

# String Theory is generally used for description of gravity and particle physics.

# String Theory was first studied in late 1960, with the rise of a strong nuclear force.

# Fundamentally objects string theory is closed and open strings model.

# String Theory has also interaction with quantum world i.e. worldlines of point like particles or sometimes called world sheet.

# In String Theory, we are likely to talk about more than four dimensions such as length, height, width and time (which is the fourth dimension).

# In String Theory there are 11 dimensions, Superstring Theory has 10 dimensions and  Bosonic String Theory there are 26 dimensions.

# String Theory is further divided into “Brane” and “Dualities”. In Brane Theory, open strings attached to a pair  known as D-Branes whereas in Dualities, it is of two kind S Duality and T Duality.

# Matrix Theory also provide some useful contribution to the string theory as in physics, matrix model gives us the behavior of set of matrices within the framework of quantum mechanics.

# There are various assumptions for string theory such as Mirror Symmetry, Calabi-Yau Manifold, Bekeinstein- Hawking formula, Quantum Gravity, Anti-de Sitter Space and many other methods for assuming the one of the most challenging concept in nature.

# Reality is what one wants to understand but still criticizes himself  / herself not because reality of ultimate nature is hidden but exists everywhere to create uncertainty.

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# “ONE WHO PLAYS WITH STRINGS”

# Brian Greene born on 9 February 1963. He was a Physicist, Mathematician and String Theorist.

# He is also a co-founder of World Science Festival.

# He has worked on Mirror Symmetry, Calabi-Yau manifolds.

# He is the author of “The Elegant Universe”, “The Fabric of Cosmos”, The Hidden Reality and many more.

# He also appeared on Television series presented by a Nova. Where he talks about universe, space, string theory and many other scientific perceptions.

# He is doing his best for science and hence talk about science, has many seminars and other discussions on science.

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