Time Reversal 2

Lessons from the Light, 5.3

They found that T is indeed violated.

All perfectly fine and glorious. The pet peeve only comes up in the sub-headline of the SLAC press release: “Time’s quantum arrow has a preferred direction, new analysis shows.” Colorful language rather than precise statement, to be sure, but colorful language that is extremely misleading.

“Time’s arrow,” in the sense that the phrase is conventionally used (by the kind of folks who would conventionally use such a phrase), refers to the myriad ways in which the past is different from the future in our macroscopic experiential reality. Entropy increases with time; … This new measurement in the B meson system — indeed, the entire phenomenon of T violation — has absolutely nothing to do with that arrow of time.

The reason is pretty simple to understand. The arrow of time centers on the concept of irreversibility — things happen in one direction of time but not the other. You can scramble eggs, but not unscramble them, etc. That’s not at all what’s going on in the B mesons. The oscillations between different types of meson happen perfectly well in both directions of time, just with ever-so-slightly different rates.

The particle-physics processes in question, in other words, are perfectly reversible. Information is not lost over time; you can figure out exactly what the quantum state used to be by knowing what it is now. (It’s “unitary,” to use the jargon word.) That’s utterly different from the macroscopic arrow of time.

— Time-Reversal Violation Is Not the “Arrow of Time”

— Sean Carroll

2014.06.13 Friday ACHK

The paradox of happiness solved

It is often said that we fail to attain pleasures if we deliberately seek them. This has been described variously, by many:

    Viktor Frankl in Man’s Search for Meaning:

    Happiness cannot be pursued; it must ensue, and it only does so as the unintended side effect of one’s personal dedication to a cause greater than oneself …

— Wikipedia on Paradox of hedonism

The paradox of happiness: 

If you do good work, you will feel happy.

However, if you do good work only because of the desire of getting happiness, you will not get it.


happiness ~ progress ~ self transcendence

do good work ~ keep going to the next levels


seeking happiness directly ~ focus on oneself ~ trapped at the same level

no progress ~ unhappiness

— Me@2011.06.22


~ 快


— Me@2014.06.13

2014.06.13 Friday (c) All rights reserved by ACHK