Here's a pdf of the article [1]. I'd love to hear a guru on quantum computation (maybe @michael_nielsen [2]) describe how quantum error correcting codes might interface with this result. I thought the whole point of quantum computing was that it needed to be reversible, so if you add quantum ECC, can you still do it?
I'm curious if the person who suggested or posted this to Hacker News knows if this is for sure cool, or if they just were dazzled (as I am) by the Q word.
As long as quantum computations employ an arrow of time there is no way to escape the before and after semantics of the second law. My gut tells me that the arrow of time and simultaneity are a gestalt. Throwing out the arrow of time takes the baby with it, i.e. what would simultaneity get us without an after and before?
Looking at the letter, once the experiment or equations requires initial conditions, there's no way to avoid an arrow of time. Change comes later. The arrow of time is a premise of the experimental method.
For me, the headline parses out to a dog-bites-man "The Second Law of Thermodynamics" with "quantum" canceling itself out. As Chevy Chase would say, Charles De Gaulle is still dead.
QECC takes "logical qubits on a larger space" to "corrected qubits on a smaller space". So while there is entropy production on the entire space (2nd law thermo), it is still possible to have entropy reduction locally.
Eg:
0) "1 important qubit in some specific pure state" (entropy=0) + "4 ancillary qubits in some known but unimportant state"(entropy=0) are made using a 1to5 QECC into:
1) 1 logical qubit(made of 5-qubits) in a pure state (entropy=0)
2) Presence of noise: 5-qubits now in mixed-state (entropy=a>0)
3) Error correction on 5-qubits turning them into:
4) "1 important qubit in some specific pure state"(entropy=0) + "4 ancillary qubits in some now-random states" (entropy>=a>0)
Surprised they gave him an Ig Nobel for something so obviously clever and useful. Perhaps the judges weren't done with breakfast when they encountered his invention.
Sorry, this was all in the sales pitch, not the science. They refolded an egg protein called lysozyme, which has been refolded countless times before without anyone talking about unboiling eggs.
"""
If the laws really are reversible, then what are the physical origins of the time-asymmetric entropy production that we observe?
The physicists explain that the answer to this question lies in the choice of the initial conditions. The microscopic laws allow reversible processes only because they begin with "a genuine equilibrium process for which the entropy production vanishes at all times," the scientists write in their paper. Preparing such an ideal initial state in a physical system is extremely complex, and the initial states of all observed processes aren't at "genuine equilibrium," which is why they lead to irreversible processes.
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[ 3.6 ms ] story [ 32.1 ms ] threadI'm curious if the person who suggested or posted this to Hacker News knows if this is for sure cool, or if they just were dazzled (as I am) by the Q word.
[1] https://physics.aps.org/featured-article-pdf/10.1103/PhysRev...
[2] https://twitter.com/michael_nielsen
As long as quantum computations employ an arrow of time there is no way to escape the before and after semantics of the second law. My gut tells me that the arrow of time and simultaneity are a gestalt. Throwing out the arrow of time takes the baby with it, i.e. what would simultaneity get us without an after and before?
Looking at the letter, once the experiment or equations requires initial conditions, there's no way to avoid an arrow of time. Change comes later. The arrow of time is a premise of the experimental method.
For me, the headline parses out to a dog-bites-man "The Second Law of Thermodynamics" with "quantum" canceling itself out. As Chevy Chase would say, Charles De Gaulle is still dead.
Eg: 0) "1 important qubit in some specific pure state" (entropy=0) + "4 ancillary qubits in some known but unimportant state"(entropy=0) are made using a 1to5 QECC into:
1) 1 logical qubit(made of 5-qubits) in a pure state (entropy=0)
2) Presence of noise: 5-qubits now in mixed-state (entropy=a>0)
3) Error correction on 5-qubits turning them into:
4) "1 important qubit in some specific pure state"(entropy=0) + "4 ancillary qubits in some now-random states" (entropy>=a>0)
An Australian man who uncooked an egg has won an Ig Nobel Prize for achieving the unintentional feat.
http://www.northerndailyleader.com.au/story/3359027/aussie-s...
> The stated aim of the prizes is to "honor achievements that first make people laugh, and then make them think".
""" If the laws really are reversible, then what are the physical origins of the time-asymmetric entropy production that we observe?
The physicists explain that the answer to this question lies in the choice of the initial conditions. The microscopic laws allow reversible processes only because they begin with "a genuine equilibrium process for which the entropy production vanishes at all times," the scientists write in their paper. Preparing such an ideal initial state in a physical system is extremely complex, and the initial states of all observed processes aren't at "genuine equilibrium," which is why they lead to irreversible processes.
Read more at: http://phys.org/news/2015-12-physicists-thermodynamic-irreve... """
... This is a writeup of a writeup of a single paper that itself cautions about experimental conditions.