Das lied von das Universum

I just read “The life of Galileo”, by Bertolt Brecht. Brecht, a man of his time, was worried about the ethics of the scientific work. My personal opinion is that it is not science itself that has to be under scrutiny, but its uses. Science has improved our lives in general, when used properly. And knowledge is a treasure for us all. Only us can save us from ourselves, and knowledge is the way to go. 

A sentence was highlighted by somebody else in the version I have been reading: “Unhappy the land that has no heroes!”. Galileo´s recantation has been cried. However, I would stick to another one, by Galileo later on in the play, which is not highlighted: “Unhappy the land where heroes are needed”.

1616: The Copernican theory is censored by the church. But, 400 years later, we “hear” the music of the Universe. When Galileo oriented the newly invented telescope to Jupiter, he started a journey, the scientific journey, that led us up to the historical moment we are living now. Much has been said and explained everywhere about gravitational waves. I am only echoing what has been on the news since last February 11^th 2016. As all good music, the timing is perfect: 100 years after they were predicted by Einstein, another science´s giant. And, of course, everybody in the planet can have a ringtone with the “music” of two black holes dancing in space. 

Since Galileo, astronomers started to see a silent movie, in black and white. Then there came the colours, with all sorts of wavelengths in the electromagnetic spectrum. Now, we can hear the sound, the soundtrack of the Universe. And now, all humanity can participate in the celebration of this gigantic step towards our understanding of the Universe. 

 We are happy, and we have our heroes.

Music from the spheres

This is a composition by Burak Ulas based on the pulsations of a star called Y Cam A. Isn´t it beautiful?

 From here.

Greetings from Earth

NASA recently released the content of the Golden Discs that are being emitted by the Voyagers. Here you can hear the greetings from Earth in 55 different languages.





Greetings :)

His Dark Materials

I recently read a fantasy book, His Dark Materials, by Philip Pullman. I enjoyed it, and I recommend it for a light reading. I’m not fan of spoilers, but I need to comment something to make my point in this entry. Sorry… 

So, in his Universe, the Dark Matter is something like particles that give consciousness to intelligent beings. They cluster around our early ancestors, when we discovered how to make tools and all that. Well, it is a fantasy book. Don’t expect it to be accurate. Or not? 

I always find interesting the selection of articles in The Physics arXiv Blog. The article that recently interested me was the one related to the relation between Cosmology and Information Theory (See here). In it, they comment the work by Fields, who proposes a hypothesis of what the discrepancy in the energy density when calculating it from physical principle and when measuring it. 

In his approach, he argues that objects such as stars and planets act in a classical way, that is, they have a specific location in space. This location is measured with respect to the cosmic microwave background. But this knowledge comes with a cost: the cost of information. 

A quantum object such as a photon or an electron are in a superposition of states, and it state is defined only when we measure it. A quantum object has a small amount of information associated to its position. However, if we know the position of an object, the information is much higher. And the point is that information costs energy. 

Fields argues that the discrepancy between theory and measurement for the energy density could be that amount of information. The mechanism for an object to become classical is known as decoherence. The quantum nature of the system (the stars, the planets), “leaks” into the environment. Decoherence means entanglement with the environment, an irreversible process from the system’s point of view. 

As I already mentioned in another post, irreversibility, time, is the arrow of increasing correlations. Decoherence is at the system’s level. The Universe might be in a pure state, but what individual pieces of it see, is something defined with respect to the environment. 

To experience time is to entangle with the other parts of the Universe, to create information. And information is knowledge. We know ourselves by experiencing time, by interacting, by defining ourselves with respect to the others. 

Is dark mater consciousness, knowledge? Sometimes fantasy is not so far from science. Just a little step further.

Nock, nock, Uni?

In the beginning there was nothing, which exploded. This is Terry Pratchett's version of the Big Bang. Funny enough, but it is more or less our understanding of the origin of the Universe. 

I read recently about this new theory where there is no singularity at the origin of the Universe. Read here, for example, for the shocking news. 

Of course, whenever I come acroos these kind of groud-breaking theories, I read as much as possible from informed places. I really like the comments in Cuentos Cuánticos (in Spanish). Basically, this person explains that yes, the Big Bang theory still holds. The thing that they changed was the singularity at the beggining of the Universe. Also, it is a mathematical artifact they use in order to remove that singularity, as physicists usually do when we find infinities. We don´t like infinities, because it means that our physical laws don´t hold there. 

And that's the conundrum: what this mathematical trick does is to remove the infinity at the beginning of the Universe, and to move the singularity to minus infinity in time. If that theory is true (something that has to be proven) it means that even at the beginning of the Universe the Laws of Physics would hold. It doesn´t mean that there is no beginning, but that at time 0 we still can use our physical theories to see what happened there. 

If no singularity exists, we will be knocking the door of the beginning of the Universe: Nock, nock, Uni? Nock, nock, Uni? Nock, nock, Uni?

I'm going to Mars!

My mom will probably kill me :)

Anyways, here you have the link to send your name to Mars. Would you like to go with me?

We are us and our circumstances

The first word in the Odyssey is “Andra”, which means man, human. In a previous post I already mentioned Prigogine's Tanner lecture "Only an Illusion" with reference to the problem of time and Homer´s works the Odyssey and the Iliad. 

The Odyssey can be viewed as a big ring composition when first Athena, a goddess, foresees Odysseus´ homecoming. For the gods, past and future are the same, and the two moments are together in Athena´s point of view. It is as if she was remembering Odysseus hardships. The main binary opposition in the poem is between mortality and immortality, how gods and humans see time. This ring composition strengthens the idea of endless time, of atemporality. 

Odysseus starts the poem in an island with the goddess Calypso, in a world that doesn´t change, apart from the human world, with no connections with it. In another previous post I mentioned the link between time and quantum entanglement, and I concluded that “time has no meaning outside the universe, and it is embedded in the relationship between its elements”. The relationships we establish with our environment determine what life is. We are us and our circumstances, as Ortega y Gasset said. 

Today I came across with an article where they explain how “The arrow of time is an arrow of increasing correlations”, as Seth Lloyd pointed out about 30 years ago. 

In another post I also mentioned how it has been proven that by using a definition of information stating which properties it should have, quantum mechanics can be derived from said properties. Seth Lloyd , by using an approach to quantum mechanics where information units are treated as the basic building blocks, ended up realizing that as the particles became increasingly entangled with one another, the information that originally described them would shift to describe the system of entangled particles as a whole. The particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individual particles contained none. At that point, Lloyd discovered, particles arrived at a state of equilibrium, and their states stopped changing. 

As Lloyd says, “the universe as a whole is in a pure state, but individual pieces of it, because they are entangled with the rest of the universe, are in mixtures.” So, does it mean that the Universe knows everything?

It is very interesting to see how physics slowly gets to the heart of the question of what means to be human. Our experience of time is intimately linked to the relationships we develop along our stay here. Physics is getting to the core of human experience, already sung by poets and philosophers.

You've got mail

Seen here :)

Quantum theory and information theory (again)

In a previous post we already talked about the relationship between quantum theory and information theory. In it, we saw how Lluís Masanes and collaborators derived quantum mechanics from a few postulates based on the properties that a unit of information should have. 

Today, I came across with two different articles that explore this relationship. In the first one, Stephanie Wehner and Esther Hanggi from the National University of Singapore’s Center for Quantum Technology, showed us that the uncertainty principle is intimately related to the second law of thermodynamics. (Note that thermodynamics are intrinsically related to information theory.) In particular, they saw how by loosening the uncertainty principle, they got more useful energy/information out of the system than they put into it thus violating the second law of thermodynamics. Since the violation of the second law is incompatible with the physics we know, this means that our ability to calculate the state of a particle with infinite accuracy (the uncertainty principle) is forbidden by the second law. Note that thermodynamics is related to the macroscopic state of a system, whereas quantum mechanics is related to its microstates. 

The second article I found interesting states that macroscopic systems cannot be quantum in nature, that is, we do not observe a superposition of states in the macroscopic world, but one only state. The author, Bolotin, states that the solution of the Schrodinger equation is just unsolvable for macroscopic objects. Bolotin says that the problem of solving Schrodinger equation is NP hard, and he shows, making a few calculations, that the computation time to solve this equation for a macroscopic state will either exceed the time of the universe, or the computation speed should be higher than the Plank time, where no state makes sense.

So the question here is, how does the universe compute its state? How does it go from quantum to macroscopic? 

I think the answer to that question goes again to the field of computational mechanics. In their article, Shalizi and Moore explain how Nature can be described in different levels of detail. They show how macroscopic states can have a higher predictability efficiency than the dynamics of their corresponding microstates. It all falls to information theory again. It their article, they define emergency of one description from the other, that is, a coarse grained version of the microstates, but with higher prediction efficiency than the other. 

It seems to me that the universe describes itself in only one way, it is only the way we look at it that separates between the different levels of description. As Shalizi and Moore put it: “for every question we ask It, Nature has a definite answer; but Nature has no preferred questions.”

Some thoughts about consciousness

The central point of Hofstadter´s book mentioned in my previous post was to see how an “I” is formed. I read some people found that the book "Gödel, Escher, Bach: An Eternal Golden Braid" has no central point, and therefore he wrote “I am a strange loop”, which I haven´t read. As Wikipedia says “He demonstrates how the properties of self-referential systems, demonstrated most famously in Gödel's Incompleteness Theorem, can be used to describe the unique properties of minds.” 

Now I´m going to be rambling about some things that I´ve been thinking about. I find myself in a strange loop, so feel free to comment if you find them to be just a bunch of disconnected thoughts, with no consistency at all. I´m only human, and I think about the Universe in human terms. 

If you have read some of my previous posts, you will find that I am asking myself if the Universe can be self-computable? In order to be so, it should be complete and consistent. As Gödel´s theorems state, it cannot be proven within itself if the formal system is as complex as arithmetic. One possibility would be the fact that the Universe is an infinite process and can check its self-consistency ad-infinitum. By metathinking, It would reach the conclusion that It can be consistent in a finite amount of time, but It would not know it until reaching infinite time. We humans (or any intelligent being) could be the way the Universe tests its consistency constantly. Could we at some point compute the Universe? That would be the Universe computing itself. And we would be theorems and universal truths.

The Universe would reference itself by means of intelligent beings as us. Perhaps the self-reference is the beginning of All, and that´s why we see it so much in Nature. A way of attaining both finite and infinite. As William Blake would put it:

To see a world in a grain of sand 

And a heaven in a wild flower, 

Hold infinity in the palm of your hand, 

And eternity in an hour. 

Quantum mechanics derived from information and computation

In their recently published paper entitled 'Existence Of An Information Unit As A Postulate Of Quantum Theory', Lluís Masanes and collaborators have derived quantum mechanics from a few postulates based on the properties that a unit of information has. 

The main idea is that information exists, and it comes in fundamental units. From the properties of this information units, called gbits, or general bits, they derive quantum mechanics. 

The main properties of this information units are: 1. Continuous reversibility, that is, for any system, and for every pair of pure states one can in principle engineer a time-continuous reversible dynamics which brings one state to the other. 2. Tomographic locality, or the possibility of constructing the state of a composite system from the simple states that form it. 3. No simultaneous encoding. It means that each gbit encodes an only information unit. 

And that's all. They find that the only generalized probability theory that is compatible with these postulates is quantum theory. They do not say what information is. They only say the requirements this information unit should have in order to derive quantum mechanics. 

This approach gives a computational point of view of the Universe. According to the authors “Any physical process can be simulated with a suitably programmed general purpose simulator.” If that's true, we could be living in a simulation. 

Full article here.

Time as an emergent property of entanglement

The holy grail in Physics is to unify quantum theory with general relativity. But, as Wheeler-De Witt showed, the "problem of time" arises when doing so. The prediction of their equation is that nothing happens in the universe, which is contrary to our experience. 

Page and Wootters found that we can describe an evolving universe from the point of view of internal observers thanks to quantum entanglement, even having a static system for an outside observer. In their article, Moreva and co-authors have shown how this can be achieved experimentally, for a toy universe. In particular, they show how a static, entangled state of two photons can be seen as evolving by an observer that uses one of the two photons as a clock to gauge the time-evolution of the other photon. However, an external observer can show that the global entangled state does not evolve (arxiv.org/abs/1310.4691). 

So, to experience time, we have to be entangled with the rest of the universe. An outsider, a God-like observer wouldn't see a difference in the state of the universe, in order for both, quantum physics and relativity to be compatible. However, all that comprises the universe would see the evolution of time, as we can experience. 

So time has no meaning outside the universe, and it is embedded in the relationship between its elements. It is an exchange of information between the different parts which are interacting within it. Note that time is related to the second law of thermodynamics, to the probabilistic nature of our experience. Interactions, as always, make all the fun.

Are we living in a simulation?

I was reading the other day about the Simulation Argument here. I found it very interesting.

 The question raised is: are we living in a simulation?

The concept was popularised by the film The Matrix. Are we living in a virtual world? The Simulation Argument states: One of these are true: (1) the human species is very likely to go extinct before reaching a “posthuman” stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation.

The argument is very simple: if there is any stage when humanity can simulate the human mind, and a lot of people are dedicated to simulate human beings, it is very probable that we are a simulation.

There are many subtleties about this postulate. The first question would be: can we simulate a human mind? If we assume that our minds are only the result of our physical substrate, then, in theory, we could do that. I say in theory because the technological problems of simulating all our neurons and their interactions would be very difficult.

But, for the sake of the argument, let´s say that we can simulate a human brain. Then, what about the universe in which it is immersed? We should simulate it too in order for that mind not to realise it is not a human being. That seems a little bit difficult. In the first place we should know everything about our universe. Could we create a different universe that looks like ours without knowing our own?

Well, the question of the universe is important if we want to create a human mind that is free in its own universe. We could just create a life sequence where the individual thinks he or she is free, but that in fact is deterministic.

It that sense, there are different kind of simulations: the life of this person is completely simulated, or only their psychology is simulated, and they are actually free; you can simulate a population, instead of only one person, both with freedom or without it. In a free simulation with a population their minds would interact and could “discover” their world as we do, that is, creating an objective reality that is made of all the common things they experience. They could develop a science in their world.

But, would they realise they are simulations? Let´s go back to the simulation of the universe. Could we simulate our universe? There are different positions: some people like Wolfram believe that we are just an algorithm, a Cellular Automata, which rules we do not know yet. But, knowing those rules and the initial conditions, we would be able to simulate our universe. However, other people think that it is not possible (see my post “What does the Universe know?”). Would we reach a point where we find the “flaws” of The Matrix?

This also creates a problem for those who think about the simulation of specific lives, such as Einstein´s life, or Napoleon´s life, etc. The Simulation Argument would give the opportunity of having a holyday by living the life of some important person in History. For that we should know, as we said, the rules and initial conditions of the universe.

If the rules were known, the initial conditions could be calculated by an optimization method, by knowing the state of the universe at one point. That is not so “difficult”: we could use the holographic principle and measure the state of the universe in its boundary only.

And that is only if the universe is deterministic. What if it is not so? Could we simulate our History? Perhaps we would be able to create Histories that look alike, but with different details (like in The Foundation series, by Asimov). Or perhaps not.

The Simulation Argument raises a lot of questions, that I think are very important. The main one is: can a human mind be simulated? Well, since I believe that we are only a bunch of atoms (or quarks, or whatever), I think that “in theory” that could be possible. Only we do not have the technology necessary to do so. Then, would it be ethic? That is another question.

More questions come to my mind, but I think I will leave it there. I hope you found it interesting too.

The pale blue dot

On July 19, 2013, the wide-angle camera on NASA's Cassini spacecraft captured Saturn's rings and our planet (see here for a complete explanation). We can see that it is a very tiny blue dot in the vast Universe. Of course, lots of people remembered the insightful comment by Carl Sagan when we first saw our planet from 6 billion km, in 1990, a photo taken by the Voyager 1: 

 "From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

 The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known." 

There is not much else to say. Just, think about it, and try to make this pale blue dot a better place.

What does the Universe know?

I recently read an article entitled "The Universe Is Not A Computer", by Ken Wharton. I found it very interesting. In it, the author explains that other point of view can be possible in Physics: the Universe is not an algorithm that is running and it's waiting to see what happens. Other formalisms in Physics are possible, where the Universe "knows" where it is going to be in the next interval of time. That formalism is that of Lagrange. 

He uses the example of a beam when it passes through a crystal. If you know the initial angle and the different refraction indexes, you can calculate the angle in which it will bent. That's the usual way of looking at it. But you also can use a formulation where you give the initial and final points. Light just go following the path of minimum action. 

So, we have two possibilities: on one hand, you give all the initial conditions and the equations, and then the Universe keeps updating its state at each interval of time or, on the other hand, the Universe knows where it started and where it is going to finish, and just follows the path of minimum action. 

The first point of view is the one physicists work with normally. It is the foundation of Wolfram's work, "A New Kind of Science". Wharton argues, however, that the Universe already knows its final state, and just follows the laws of physics. 

Note that both points of view are deterministic. In the second case it is obvious. In the first case, the Universe only follows the laws and its future was determined by its initial conditions. 

This article reminded me Prigogine's Tanner lecture "Only an Illusion", and the opposing ideas about time he talks about: is there an absolute point of view, where past, present and future are the same, or there is only the human point of view, where we are irremediably linked to the passing of time? For humans, the answer is clear: we cannot escape time. However, the point of view of the Universe could be different. It contains all that there is, and "knows" perfectly its laws. 

In "Only an Illusion" we can read the conversation between Einstein and Tagore about the nature of human's truths. Einstein believed in a Truth independent of human's mind. Tagore, however, stated that humans can only grasp human's truths. Does the Universe "knows" the Truth, or does it have to wait until the end of time to "know" it?