Why don't Einstein's gravity and quantum mechanics work together?

Question

I am researching string theory and it keeps saying that the largescale idea of einstein's gravity doesn't mesh with quantum mechanics of small small particles....but why? and why is string theory so important in solving this problem?

Answer 1

It is a misconception that gravity and quantum mechanics do not work together.

For starters Newton and Einstein's theories on gravity never explained what gravity is. They merely predict the effect it has on matter and later space time. Newton explains the effect in terms of a force acting between two masses. Einstein explains it in terms of mass causing a warp in space and time. Quantum mechanics is more of a why explanation as it defines a mechanism by which gravity operates -- in terms of massless virtual particles being exchanged between various real particles in the universe. See quantum gravity. All three theories similiar predictions for everyday objects. Choice of which one to use is typically driven by convenience. Quantum gravity makes a few predictions on the existance of these massless particles and which may be testable. I.e. we may be able to 'find' these particles or others which are predicted.

Quantum mechanics also provides a mechanism for the three other forces in the universe -- electromagnetic, strong nuclear, and weak nuclear forces. At the sub-atomic level, these forces dominate over gravity to such a point that gravity is almost always excluded for the calculations. Recent theories predict that at high energies these three forces are esentially the same. So far, quantum mechanics can not make the same predictions for gravity.

String theory is one attempt to try to explain why all these particles in quantum mechanics look and act the way they do. Why do virtual gravitons pull other particles closer together? Why do the particles making up the electromagnetic forces and nuclear forces become the same at high energies? The hope is that given such a theory will also find a relationship between quantum gravity and other particles, lead to new predictions which might be testable, or explain how all four forces might related at even higher energies.

So far string theory has not been able to model quantum mechanics terribly well.

Answer 2

Einstein gravity is for objects with high mass and large size which says that everything has a sure possibility.
like Einstein says that the planets including our earth revolve around the sun and will keep revolving around it.
But quantum mechanics is totally based on probability.
for the above case quantum mechanics says that there is a possibility(though very minute and thus negligible) that the planets might leave their orbits and start moving haphazardly
Einstein's laws say that one can not run through a solid wall but quantum mechanics says that if one keeps pushing a wall for an eternity one has a fair chance of going through it which practically almost impossible
the string theory is a very new theory brought up by Stephen Hawking that says every form of energy and matter (i.e. everything is this damn world!) is made up of strings which are so small that if we take an atom to be the size of our solar system and the sun being the nucleus and the planets being the electrons then a tree on earth will be the size of the sting.
the string theory says that the way the string vibrates and moves that is unique for a particular matter and form of energy and force.
so this string theory becomes a unifying bond between einstein's theories and quantum mechanics

Answer 3

Einstein's Theory of General Relativity deals with the movements of very large, very massive objects curving the smooth geometric fabric of space-time around it. It is elegant and based on geometry and order.
Quantum mechanics on the other hand deals with the random movement of point-sized particles like electrons. Quantum mechanics is based on the Heisenberg Uncertainty Principle which states that you can never find out the exact speed and position of a particle at the same time. Here, at the very minute level, space-time begins to froth like foam and bizarre things start to happen like quantum tunneling in which a paricle instanteously 'jumps' from one point to another. At this level chance rules and anything is possible.
String theory theorizes that all matter is made up of vibrating strands of strings of energy. How the string vibrate dictates the nature of a particle. String theory is the serious contender for a Theory of Everything as some of its calculations point to a representation of gravity, thus it could unify General Relatvity with Quantum mechanics.

Answer 4

Einstein General Relativity Field Equation as well as the principle of equivalence do not take into account"temperature" which exists In the microworld of atomic structures(Quantum Physics.)

The Einstein Field Tensor Equations do not relate the Effects of Magnetism or Temperature Energy in the Space and Time structures levels of the Universe.

Strings Theory does not compare to the Einstein Relativity Theories. Even though they have one Scenario in common ;They both use a manifold of space. Einstein relativity alludes that the Universe is made up of "Space-Time".
String Theory alludes that the Universe is made of little "Strings" that shake.
There is no description of causality in the motion of space time. By the same token no description on the cause of motion of a String.

Therefore the mechanism of gravity still remains unexplained in General relativity Theory ,Strings theory and Quantum Mechanics.

Answer 5

It's because quantum mechanics should be able to explain where gravity comes from at the small scale, and it doesn't. As successful as it is, it can't be considered a complete theory until it does. Then along comes string theory and pops out a small-scale gravity prediction. Unfortunately, string theory can't be experimentally validated with existing technology, so we wait. It has other problems, as well, which is why M-theory came along after it (link below).

Answer 6

Gravity and quantum mechanics do work together, as evidenced by the existence and functioning of our universe. We just don't understand how. We have theories that work well on the relativistic scale, the everyday scale, and the quantum scale. We just don't have a single theory to cover them all.

So many people think string theory has that potential, that a disproportionate share of modern physics effort is spent on that endeavor. Some, including Lee Smolin, think it's a bad choice to put so many of our research eggs into that one basket.

Answer 7

ofcourse string concept is larger susceptible in direction of quantum mechanichs it fairly is an area of quantum mechanics. unproven at that. the smallest unit so a approaches suggested are quarks. string concept is the hypothesis that each and each and each and each and all of us remember is in right away forward words vibration of ability. as for loop quantim gravity. the call says all of it, gravity loops. in relativity gravity can distort area and time (now no longer remember, yet area) if gravity gets sufficiently great, it particularly is going to loop spacetime, and create what we call a quantum singularity, area of interest the situation all in spacetime is compressed to a minimum of one sigle element. (black hollow)