According to GTR, gravity is not a force but effects of gravity is because of the shortest path which object follows. Since locally the space time is flat then one cant define energy density associated with gravitation. Gravitational waves are just space time variation which object follows. But if this is true then object gains energy according to inertial frame because object starts to move under influence of gravitational waves. Since energy is conserved and because of gravitational waves object is moving then does it means that gravitational waves have energy? Does having energy in gravitational waves means that GTR need quantization? Because energy needs a particle (graviton) to exist, like in electromagnetic field photon are carrier of electromagnetic field.
Edit: In theory gravitational waves can always have enough frequency (hence the wavelength) such that it interacts with electron. But if these gravitational waves do not have enough energy (but have wavelength of the order of electron size so that they can interact with electron), such that electron can excite to higher level of the atom. Then according to quantum mechanics since energy is not sufficient then the electron wont absorb gravitational waves energy. It directly means that electron wont move under space time variation. How can, matter have mass m will not move under space time variation? Does that constrain gravitational waves to have same constant "h" such that for given wavelength, the energy have to be that much sufficient such that electron will excite to other level? Or does it mean that we cant have wavelength of the order of electron size (which is not defined) in QM.
Dear Sourabh
You are absolutely right, everything is confusing. My opinion the whole GR and SR is not working with universe that we are exploring. Here is quantum mechanics gravity Article Quantum Mechanics Gravity, Mechanical Gravity of Newton is Myth
maybe it clear some fog out of your thought. best regard.
Yes gravitational waves do carry energy and momentum. No, the fact that they do doesn't imply that energy is quantized. At the scale, where the description in terms of waves is adequate, which is the case, the fluctuations due to gravitons, the quanta of the field, are negligible. Just as is the case for electromagnetism.
Gravitational waves are nothing more and nothing less than variations of space and time-soacetime doesn't have a fixed geometry.
Javad Fardaei and Stam Nicolis ,
Thanks for your clarification. Even recoiling of astronomical object by astronomical objects confirms that gravitational waves should have energy and momentum. But as far as QFT is concerned we need a particle such that graviton interacts with space and time to make the curvature. But I do not understand one more thing, In theory gravitational waves can always have enough frequency (hence the wavelength) such that it interacts with electron. But if these gravitational waves do not have enough energy (but have wavelength of the order of electron size so that they can interact with electron), such that electron can excite to higher level of the atom. Then according to quantum mechanics since energy is not sufficient then the electron wont absorb gravitational waves energy. It directly means that electron wont move under space time variation. How can, matter have mass m will not move under space time variation? Does that constrain gravitational waves to have same constant "h" such that for given wavelength, the energy have to be that much sufficient such that electron will excite to other level? Or does it mean that we cant have wavelength of the order of electron size (which is not defined) in QM.
Thanks.
The fact that electrons bound in atoms can't absorb or emit arbitrary amounts of energy doesn't mean anything more than the fact that gravitational waves can't be detected by monitoring such processes.
Stam Nicolis True, because wavelength of gravitational waves is so large. My question is, if the wavelength is of the order of the electron or atom itself (Infrared spectroscopy, because there exist levels in molecules too).
My question is the fact fact that gravitational waves cant be detected by electron or molecule: is because of the theoretical limit or experimental limit?
Gravitational waves carry both energy and momentum and the values are equal (in consistent units) so they travel at the speed of light.
The first formal detection was an event that, during the last cycle or so, radiated more energy than all the stars in the universe, an astonishing gravitational luminosity.
The momentum carried by the waves is also expected to cause the resulting black hole to "recoil" after a merger, that's very important because it implies that BH formed in a dense cluster are likely to be ejected so not be able to merger a second time producing a hierarchy of masses.
George Dishman and Konstantin M. Golubev Thanks, I have to see your paper. So you are claiming E=Pc. Is there any reference paper for that.
But since m=0 then it should be E=pc for gravitational waves.
Dear Sourabh,
SS: So you are claiming E=Pc. Is there any reference paper for that.
I don't know of any paper but it will be in every textbook, it is a fundamental property of a photon.
p = h / λ
E = h f
λ = c / f
where h is Planck's constant.
https://en.wikipedia.org/wiki/Photon#Physical_properties
SS: But since m=0 then it should be E=pc for gravitational waves.
That's correct.
George Dishman
Still one question remains that if gravitational waves have energy and so how can we move forward with this :
In theory gravitational waves can always have enough frequency (hence the wavelength) such that it interacts with electron. But if these gravitational waves do not have enough energy (but have wavelength of the order of electron size so that they can interact with electron), such that electron can excite to higher level of the atom. Then according to quantum mechanics since energy is not sufficient then the electron wont absorb gravitational waves energy. It directly means that electron wont move under space time variation. How can, matter have mass m will not move under space time variation? Does that constrain gravitational waves to have same constant "h" such that for given wavelength, the energy have to be that much sufficient such that electron will excite to other level? Or does it mean that we cant have wavelength of the order of electron size (which is not defined) in QM.
Thanks
The gravitational waves seen so far have frequencies up to a few tens of Hz for BBH mergers and a few kHz for the one BNS merger seen. That means the shortest wavelengths are around 100 km. You can't get two stars to orbit any faster than a pair of neutron stars.
The constant h is just a way of normalising measurement units, the equations apply to any massless effect.
The wave alters the metric of spacetime by a very small amount. The strain seen in the detections to date has been less than 1 part in 1023 so the diameter of the Earth which is around 104m would be altered by about 1-19m, or less than a millionth of the size of one atom accumulated over the width of the whole planet.
This seems to be true, As far as measurements and BNS mergers are concerned. Thanks.
Space is never empty, it always carrying wave, if there is temperature. Space of universe also is intelligent and carrying character. But there is no movement of anything between galaxies, because there is no wave-temperature.
Dear Sourabh Singh,
Your question is excellent! My response is yes, but not in base of GTR and gravity theory of Newton…
Rest please read my article: https://www.researchgate.net/publication/327201504_Gravity_a_paradym_shift_in_reasoning,
You will find ideas how you can do it!
Regards,
Laszlo…
P.S: the article is not public, but if you want I send you
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