能量不守恒及經典薛定諤貓？

戴榕菁

物理學家Sabine Hossenfelder在她的視頻中指出宇宙膨脹導致宇宙內的總能量不守恒，原因是宇宙膨脹使得行進在宇宙中的光的波長增加，因而能量減少，而這部分減少的能量沒有參與到任何能量交換的過程，因此這部分能量就白白地從宇宙中消失了。

按照她的這種說法（聽起來挺有道理的，我現在也找不出她這種說法有什麽毛病來），其實可以得出結論說不需要膨脹宇宙中的總能量也不守恒，因為在任何兩個相互離開的物體之間都會產生紅移，而在任何兩個相互趨近的物體之間都會產生藍移，其中紅移損失的能量就白白地沒有了，而藍移增加的能量也是憑白地產生的。試想你在宇宙飛船上射出一束藍光，它的能量是hf，其中h是普朗克常數而f是光的頻率。這時後麵一艘與你同速的飛船接收到了你的這束光，它仍然是藍光；然後，後麵那艘飛船突然減速，這時你又射出一束藍光，仍然被那艘船接收到了，但是它已經沒有那麽藍了，而這由於紅移損失掉的能量並沒有轉換成任何其它的能量，而是就這麽白白地不見了。

如果你說在整個宇宙中紅移產生的能量與藍移產生的能量可以抵消掉因而總能量不變的話，那也已經不是我們現在所說的能量守恒的意義了，而成為在統計意義上的能量守恒了！

不僅如此，由於紅移和藍移的能量損失是由光的接收體決定的，因此一束光打出後，它的能量到底是會因為紅移而損失，還是因為藍移而增多，或是保持不變，那是要等到它被一個物體接受到的那一瞬間才決定的。但是，這裏的要害在於，紅移損失的能量或藍移增加的能量本身卻不是由接受物造成的，而是在光的傳播過程中出現的，因此，這裏的能量變化就如同是經典意義（即不涉及量子意義）的薛定諤貓，而且是無時不在的真實的薛定諤貓，它的實際狀態是由觀察者的狀態決定，但它的狀態卻是在被觀察之前就已經注定了的。

物理學出現了悖論？？？

[慕容青草]

下麵是在網上與英文讀者就本文英文版的對話 (https://www.academia.edu/s/49453d40aa#comment_770918)：

Eduardo D Dib23 hrs ago

Doesn't have the velocity of spaceship B to be modified in order to change the shift? That requires energy, possibly compensating the loss due to the shift...

rongqing Dai23 hrs ago

The energy changes is irrelevant to the change of the wave length of the photon....actually you might even say the total of the red shifts and blue shifts in the universe might cancel each other to keep the total energy the same...but that would no longer be the same sense of the energy conservation as we have been assumed, because that would be the energy conservation in a statistical sense....Thanks

rongqing Dai22 hrs ago

Put it this way: When the mass of spaceship B changes, the energy that used to change its speed would change, but the loss of the energy of the laser beam would not change, which is only related to the amount of the speed change...so that energy cost for changing the speed of spaceship B does not come into the equation of energy conservation (or nonconservation) of the laser beam at all...

Eduardo D Dib12 hrs ago

However, the amount of the speed change itself is related to the amount of energy used to produce it. So, there is not a covariant relation linking the energy loss of the beam with the specific amount of energy used to produce that specific speed change? The more energy used in decelerate B, the more energy lost in the shift. Nothing random there...

rongqing Dai12 hrs ago

the deceleration is the illusion in my layout of the scenario for the sake of comparing "no change" and "loss"....we don't need the deceleration...the whole point is the relative departure of two spaceships...look at it this way: we have three spaceships: A, B, C...and John in A shoots a blue laser beam to B which is received by Jack on B without any energy loss because those two spaceships moving at the same speed, but then he shoots another blue beam laser to C, and received by Joe on C which is so much slower than A, and what Joe received is red laser beam.....the energy loss goes to nowhere, but just completely lost...The weirdest thing here is that when John shoots out the laser beam, nobody knows whether the energy would be conserved or changed until it hits the retina of Joe...