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Hiền T Quan
Works at IT Profressional with interests in Computers, Electronics, Photography, Open Source Software, Linux, Ruby/Rails.
Attended University of Southampton
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Hiền T Quan

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Productivity with a new font?
 
Yet another new coding font.... Nice looking. 
Hack | A typeface designed for source code
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I guess it's a case of before you preach, you'd better put you're house in order first
 
"For the last 150 years, the West had coal - they reached a stage of development with $40,000-70,000 per capita income and want poor Indians with $2,000 per capita income to reduce use of coal."
 Ahead of the Paris meet on climate change, Power Minister Piyush Goyal on Friday said coal-based thermal power will remain the staple power source for India and denounced Western concerns over climate and environmental hazards.
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Mesmerizing.
 
Pendulum balls (well, not quite, two strings for each) exhibit wonderful motion.
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You won't believe what this guy thinks of annoying clickbate titles! 
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Very interesting, I'm going to remember "低头族"
Think back with me, if you will, to middle school. If your experience during those awkward days was anything like mine, then you might remember watching your classmates as they formed various cliques. Soon most people were instantly identifiable as being one of the “loners” or the “cheerleaders” ...
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Interesting to see kids come up with solutions to real world problems. 
Kids don't want to code. They want to solve problems us oldies can't perceive
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What is the Black Hole Information Paradox? What is "information" anyway?"

Just now, +Debashish Samaddar asked me a really great question. +Ethan Siegel and I reshared an article by +Sabine Hossenfelder on black holes. In it, +Sabine Hossenfelder mentioned the "black hole information loss paradox."

He asked

What "information" exactly is encoded and/or allegedly lost and found? It's not like a computer. Information is a subjective word. If there is no subject (i.e. a person with a system of language and logic etc.) then there is no information.

Here's my answer.

In the land of physics, information is not subjective. The black hole information paradox has to do with making a prediction.

Take all the molecules of gas in a sealed room. At any given moment in time, if you give me the positions and velocities of all the gas particles, I can predict where they will be in the future or in the past, with perfect accuracy, at least in principle. (In quantum mechanics, the same idea holds... the only difference is that I can only predict probabilities, not actual positions.)

Now imagine there was a black hole in that room. I can predict future states, but not past states, because if a particle falls into the black hole and hits the singularity, it is destroyed, never to be seen again. And I don't know if this has already happened.

Technically this isn't a problem if there's no singularity, because then the singularity will never eat the particles and, encoded behind the event horizon is the information I need. In fact, technically, this isn't even a problem if the black hole exists forever.  This is because the black hole singularity isn't a place, it's a time. It's a point in the future, so with the correct definition of time, it doesn't make sense to take positions and velocities after something falls into the singularity. There is no after.

But real astrophysical black holes are not eternal. They form as the result of gravitational collapse and they eventually (after a really really long time) disappear because they lose all their energy to Hawking radiation. So, from our perspective, the black hole exists for a time and then vanishes. Now it makes sense to ask what happens after things fall into the black hole. Can we look back at the universe as it is now and figure out how it was in the past? Not with evaporating black holes we can't.

Unitarity

In quantum mechanics, this "predictability" manifests as a "conservation of probability" we call unitarity. And the total amount of uncertainty due to the probabilities is called the "entropy." (This is not the only definition of entropy. It has a different but related meaning in statistical physics, where it always increases. I'm sorry.) Fundamentally, this definition of entropy should be conserved over the whole universe. And this entropy is the "information" that is lost in a rigorous mathematical sense.

The problem is that Hawking radiation carries no entropy out of the black hole. So when the black hole evaporates, the entropy is lost with it. If Hawking radiation carried the entropy, we'd be A-OK.

Quantum Gravity

It's worth noting that we don't really think that there's a singularity at the center of a black hole. The singularity appears because general relativity is incomplete and we can't make a good prediction there. We hope that when we successfully combine quantum mechanics and general relativity we'll figure out what's actually inside a black hole.

This is why the black hole information paradox is an important problem in theoretical physics. It's one of the few ways we have to explore quantum gravity effects. By seeking a resolution to the paradox, we may gain hints about how quantum gravity actually works.

(Image credit: http://muonray.blogspot.ca/2014/03/black-hole-information-firewall-paradox.html )

The original share is here:
https://plus.google.com/+JonahMiller/posts/BQtyaMnCXTF
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Thanks for the reshare, +Hiền T Quan​!
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Though they are millions to billions of times the mass of our sun and gobble every stray star, planet and wisp of dust that wanders by, supermassive black holes are rather shy types.They are thought to exist in most if not all large galaxies, but they typically hide behind clouds of gas and dust, hampering efforts to better understand them. This summer, however, a group of astronomers at Durham University in England reported that they had used NA...
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Decided to walk to the train station in the rain yesterday. I would have missed these photo opportunities had I taken the tube.
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 ·  Translate
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Via +Glen Thomas
 
PUNISHMENT FOR USING THE PHONE DURING A CONCERT
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I discovered another photographic perspective yesterday while looking out of the train window. I call it Blurry and Focussed

Can you see why?
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I like it. I like it a lot.
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So much of life is spent striving, we hardly notice we’re doing it. Chasing after more keeps our attention on what we don’t have and prevents us from enjoying all that we do have. It’s a socially sanctioned, yet insidious habit that plagues us no matter how much we achieve or acquire. When we intentionally shift our focus to the good fortune we already enjoy, we develop a remarkable sense of freedom and contentment. Gratitude is the shortcut to the Now and that is…

The best place to be.

Jarl and Steve, Founders of Gratitude 24/7
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Occupation
IT Professional
Skills
IT/IS Ninja.
Employment
  • IT Profressional with interests in Computers, Electronics, Photography, Open Source Software, Linux, Ruby/Rails.
    present
  • Saba Software
    IT Consultant, 2006 - 2015
  • WILink Ltd
    Senior Technical Architect, 2002 - 2005
  • WILink Ltd
    Head of Systems Administration, 1999 - 2002
  • Motorola LMPS
    Development Manager, 1996 - 1999
  • Nokia Mobile Phones
    Design Engineer, 1993 - 1996
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Other names
Hiền T Quan
Story
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To paraphrase Bruce Wayne - " It's not who I am underneath, but what I post, +1, re-share and comment that defines me."
Introduction
Father to three beautiful children.
Husband to a beautiful wife.
Son to a caring mother and a guiding father.
Brother to an adventurous sister.

Grateful to have a loving and supporting family - well... more like a clan!
Grateful to have very good friends.
Grateful to have friendly and understanding work colleagues.

Loving my interactions with people on G+

Trying to reciprocate the good deeds that I have received from people over the years.
Bragging rights
Interests: Photography - Linux - FOSS User/Developer - Ruby/Rails - Android - Finding the middle path.
Education
  • University of Southampton
    Masters in Electronics & Information Engineering, 1989 - 1993
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