Time Reversal Symmetry Operator | Quantum Mechanics

[@geoffrygifari3377]

when i was first introduced to this operator, i thought time reversal operator looked closer to parity than it was to reversing motion (because of the t -> -t part), turns out time-evolution operator is needed alongside reversal for the system to change the order of events, "evolving" backwards

[@hq7908]

At 1:21, why is it not -i instead of i, as T is antilinear ?

[@PrettyMuchPhysics]

At that point we did not yet assume that T is anti-linear, we just let t -> -t, without using T as an operator. At the end of the calculation, we saw that instead of explicitly letting t->-t, we can use an anti-unitary operator in the Hilbert space!

[@hq7908]

@@PrettyMuchPhysics Thanks I see, so then we suppose that H is a real operator ?

[@FrivolousMatter]

At 2:18, there shouldn't be a minus sign in the exponent for psi~ of t~.

[@PrettyMuchPhysics]

Great catch, thank you! We decided to cut that part out, since it wasn't a good example anyway 🙈 Thanks for letting us know!

[@kshitijsinha8703]

Great video! Which application are you using btw?

[@PrettyMuchPhysics]

Thanks! We use an iPad app called "Explain Everything"!

[@xenomyr]

Do you know about the Janus Cosmological Model by physicist J-P Petit ? His model is bimetric with variable speed of light AND describes "dark matter" as negative masses that attract themselves but repel our ("positive") masses and vice versa. It has a website if you are interested.

[@nickallbritton3796]

ok but you know that that's not "dark matter" as in that model would obviously not fit our observations of dark matter. Dark matter is the name given to the set of observations of matter that we can see that do not fit our predictions of how they should move based on our estimates of visible matter. Hence if dark matter doesn't attract our normal "positive" masses we would not have observed dark matter

[@CM-sj9pb]

There is no time as a body or materia as waves or atoms are. "Time" is just a word that is used to make plans and schedules depending on the rotation of the planet around it`s axis and sun, because we depend from light. When somebody asks " What time it is?" he asks in fact what is the actual position of the point from the planet he is right now in comparison with the star that is lighting the planet on which he is. The feeling of "time" is introduced by other creatures in us that rule this planet and they trick us. The 12 "clock" device shows the complete rotation of the planet, divided into 12 parts, which we use to organize our plans in the continuous present or after this present. This full rotation of the planet could be divided by 60, 79 or 5698.34, etc. On a planet where there are also living beings, their "watches" could be divided by 458 or 7293 etc. language is a tool, and many languages on our planet were created by other live beings who control this planet. Anyone can create a new language in 4 hours if no one is holding him. Making a word in a new language for humans which can hear, see and talk is assigning sound + image or movements of body. There were made so many languages on this planet and with so many designs by somebody who control us as an experiment in order that humans could hardly communicate one with another. in nature nobody and nothing has name. Someone puts(tags) a sound(name) or also a shape(more letters to form a word), in case he has a language or languages, to somebody in order to shout from distance that person if there are more persons or with other reasons. A human or another live being can somewhere have as many names as someone tagged to them for their personal targets. From start(birth) humans have no language tool and you have to make one from zero or somebody else is giving you some shapes(letters) with sounds and is showing you with body movements and pointing to an object to set that sound to that object in that particular language. Or you can make no language in case you have no need for that. A healthy human can hold in his memory hundreds of languages (sounds tagged to objects or images, and movements), but there are invisible creatures that hold us and make experiments on us and put roles on everyone, religion programs, diseases, life span etc. Only these creatures that hold us in captivity know how long a human live, it may be 190 years or 500 etc. it is enough looking at the pyramids of Cheops and ancient buildings in Peru to understand that this planet is ruled by other creatures. For example, in order to create one stone for masonry similar to those from Peru, you will need computer controlled 5-axis cutting machine, not with drills, but with plasma or other methods, because all the sides are wavy and there are buildings where the stones are completely smooth, in those buildings each stone is of a different irregular shape and is made exactly for that position where it stands in the wall, and the contact between the blocks is without cement and touch among them so perfect that you can’t put a razor blade in. The granite chambers in the pyramid show the same technology as in Peru. These invisible from distance controlled tools/or maybe creatures enter in the bodies of humans or other creatures and choose who to be some king on this planet, who to be a slave, a successful holywood actor, who is a bum, who to have cancer etc. they make languages on their planets etc. and in some films they show about their secrecy and form of government. Also, who saw the first film Men in Black, there are shown at the end the hands of some creatures that play with some balls galaxies. In the very end of the movie Star Gate (1994) they show about themselves being invisible in their body. Also they show their theatre in Hard to be God (1989),a soviet-german made movie. kzbin.info/www/bejne/mWTWmK2onNWhbtU kzbin.info/www/bejne/apLIf59jYrB2hq8 kzbin.info/www/bejne/gmLad42PbMhsgdk peruviptravel.com/en/sacsayhuaman-satisfied-falcon/ kzbin.infoPg7Mktp78DE?feature=share

[@chillphil967]

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