Nearly Perfect Efficiency - 2nd Law of Thermodynamics

[ObjectivelyRational]

Recently read this article on Physorg:

https://phys.org/news/2018-01-efficiency.html

My questions are:
1. If "converting" information into energy requires a system (the demon I suppose) having a photodiode, processor, laser (light trap) all expending energy in order to cause the conversion, (i.e. the demon works ON the trapped particle) then how can it be said that "none of the information is lost but is instead almost entirely converted into work". i.e. How can we exclude the idea that work was provided to the system from the "outside" in an amount that looks like it was created by the "information" of the trapped particle?

2. What is the difference between the "traditional" second law of thermodynamics and the "generalized" second law of thermodynamics?

3. What factors determine conceptually when it is reasonable to describe some part of a system as "the" system, and to ignore the whole system (i.e. everything interacting with it), when discussing things like "efficiency" and the second law of thermodynamics?

 

[DrDu]

I think this is in principle well known. Bennett and Landauer did show that in principle all operations of a computer can be performed reversible with the exception of the deletion of the memory. The physical entropy produced on deletion of the memory corresponds exactly to the information entropy of the memory. Hence a demon can produce work at the expense of his memory storing more and more information. In a true thermodynamic cycle, also the demon has to return to it's initial state, so that his memory has to be cleared. This produces the entropy for the whole process to be compatible with the second law.

 

[Lord Jestocost]

Bennett and Landauer did show that in principle all operations of a computer can be performed reversible with the exception of the deletion of the memory.

It seems that there a still some debates with respect to this when looking at some publications by J. D. Norton or L. B. Kish.

 

[ObjectivelyRational]

Could some kind person address my specific questions? I am genuinely curious.

 

[jartsa]

Recently read this article on Physorg:

https://phys.org/news/2018-01-efficiency.html

My questions are:
1. If "converting" information into energy requires a system (the demon I suppose) having a photodiode, processor, laser (light trap) all expending energy in order to cause the conversion, (i.e. the demon works ON the trapped particle) then how can it be said that "none of the information is lost but is instead almost entirely converted into work". i.e. How can we exclude the idea that work was provided to the system from the "outside" in an amount that looks like it was created by the "information" of the trapped particle?

2. What is the difference between the "traditional" second law of thermodynamics and the "generalized" second law of thermodynamics?

3. What factors determine conceptually when it is reasonable to describe some part of a system as "the" system, and to ignore the whole system (i.e. everything interacting with it), when discussing things like "efficiency" and the second law of thermodynamics?

1: They did not claim that the collection of information was efficient, only the 'conversion' of the collected information was claimed to produce almost as much work as is possible according to the generalized second law of thermodynamics.

2: I guess a generalized engine consists of a heat source, a heat sink and an information source, while there's no information source in a diesel engine.

3: I have no idea.