physics4me

physicsgg

Archive for the ‘philosophy’ Category

Gauge Symmetry, Spontaneous Breaking of Gauge Symmetry

leave a comment »

Philosophical Approach

Pascal Lederer
This paper deals with the ontology of the vector potential. When the state of the system has the full gauge symmetry of the Hamiltonian, the electromagnetic vector potential may be interpreted as a convenient tool of a mathematical formulation, with no ontological meaning.
I argue that this interpretation is in difficulty because the vector potential becomes proportional to the supercurrent in the superfluid phases, which are spontaneously broken gauge symmetry phases, where particle number is not conserved.
I suggest that when gauge symmetry is spontaneously broken, the vector potential becomes an emergent material object of nature.
Read more at http://arxiv.org/pdf/1401.8146v1.pdf

Written by physicsgg

February 3, 2014 at 12:53 pm

The Most Abused Principle in all of Science

leave a comment »

Could you touch on the Anthropic principle and our finely-tuned Universe?
triplealphaHow the mis-application of the Anthropic Principle has led factions of scientists away from the search for a natural, physical explanation of our Universe, and why that’s bad for everyone.
…………………
Read more at https://medium.com/starts-with-a-bang/6686756f85b3

Written by physicsgg

January 4, 2014 at 4:25 pm

The Existence of Nothing

with one comment

2013 Isaac Asimov Memorial Debate


The concept of nothing is as old as zero itself. How do we grapple with the concept of nothing? From the best laboratory vacuums on Earth to the vacuum of space to what lies beyond, the idea of nothing continues to intrigue professionals and the public alike.

Join moderator and Hayden Planetarium Director Neil deGrasse Tyson as he leads a spirited discussion with a group of physicists, philosophers and journalists about the existence of nothing. The event, which was streamed live to the web, took place at the American Museum of Natural History on March 20, 2013.

PANELISTS:

J. Richard Gott, professor of astrophysical sciences, Princeton University, and author of Sizing Up the Universe: The Cosmos in Perspective

Jim Holt, science journalist and author of Why Does the World Exist? An Existential Detective Story

Lawrence Krauss, professor of physics, Arizona State University and author of A Universe from Nothing: Why There is Something Rather Than Nothing

Charles Seife, professor of journalism, New York University, and author of Zero: The Biography of a Dangerous Idea

Eve Silverstein, professor of physics, Stanford University, and co-editor of Strings, Branes and Gravity

The late Dr. Isaac Asimov, one of the most prolific and influential authors of our time, was a dear friend and supporter of the American Museum of Natural History. In his memory, the Hayden Planetarium is honored to host the annual Isaac Asimov Memorial Debate — generously endowed by relatives, friends, and admirers of Isaac Asimov and his work — bringing the finest minds in the world to the Museum each year to debate pressing questions on the frontier of scientific discovery. Proceeds from ticket sales of the Isaac Asimov Memorial Debates benefit the scientific and educational programs of the Hayden Planetarium.

Written by physicsgg

March 23, 2013 at 1:18 pm

Posted in COSMOLOGY, philosophy

The Doomsday Argument in Many Worlds

with 2 comments

You and I are highly unlikely to exist in a civilization that has produced only 70 billion people, yet we find ourselves in just such a civilization. Our circumstance, which seems difficult to explain, is easily accounted for if (1) many other civilizations exist and if (2) nearly all of these civilizations (including our own) die out sooner than usually thought, i.e., before trillions of people are produced. Because the combination of (1) and (2) make our situation likely and alternatives do not, we should drastically increase our belief that (1) and (2) are true. These results follow immediately when considering a many worlds version of the “Doomsday Argument” and are immune to the main criticism of the original Doomsday Argument.

Austin Gerig
Imagine you are sitting at a table, blindfolded, and that an urn is placed in front of you. You are told this urn can be one of two types:
it is either a small urn or a large urn.
If it is a small urn, it contains 10 balls numbered 1 through 10.
If it is a large urn, it contains 1 million balls numbered 1 through 1 million.
You currently do not know whether the urn is small or large, but would like to find out. Suppose you randomly draw one ball and find it numbered 7.
Given your draw, with what probability is the urn small?

Let T1 and T2 represent the theories that the urn is small and large respectively, and let D represent your data, i.e., that you have drawn the number 7.
Assuming you believe the urn equally likely to be small or large before you draw a number, then according to Bayes’ Law, your updated belief in T1 conditioned on observing your data is,
You therefore should believe the urn is small with almost certainty.
Notice that you have become confident in the size of the urn with only one draw.
Now, multiply the number of balls in each urn by 10^10 and imagine they correspond to birth numbers within our civilization, i.e., Adam drew number 1, Eve drew number 2, and so on (you and I have drawn numbers around 7 × 10^10).
T1 and T2 represent two competing theories, which we initially treat as equally likely. Under T1, the urn is small and contains only 10^11 numbers, which means only 10^11
people will ever exist and our civilization will die out within the next few centuries. Under T2, the urn is large and contains 10^16 numbers so that our civilization is large and will continue on for many years into the future.
As before, you would like to determine whether the urn is small or large, i.e., whether our civilization is small or large.
Given your data, D = 7 × 10^10, how should you update your belief in T1?
Without any compelling argument to the contrary, you should update it as before,
which means you should believe with almost certainty that our civilization is small and will die out within the next few centuries.
This argument is the Doomsday Argument (DA) as presented in Leslie (1989) and Leslie (1996)1.
The details of the DA can be restructured –the numbers can be changed, more urn types can be added, etc. – but the final result remains unchanged: when we condition on our birth number, we must drastically increase the probability that our civilization will soon die out.
There are many critiques of the DA, which I will not focus on here (see Leslie (1996) or Bostrom (2002) for a full treatment).
By most accounts, the DA has stood up to all criticisms except one.
As first mentioned in Dieks (1992) and expanded in Bartha and Hitchcock (1999) and Olum (2002), the DA fails to consider that you are more likely to exist in a large civilization than a small one.
This missing step exactly cancels the updating of your beliefs so that your original prior is retained.
In this paper, I intend two things: (1) to defend the counter-argument to the DA developed in Bartha and Hitchcock (1999) and Olum (2002),and (2) to show that this counter-argument does not work when the DA
is modified to allow for many worlds.
The take-home message is the following: given that we exist in a civilization that has produced 70 billion people so far, we should drastically increase our belief that many other civilizations exist and that nearly all of these civilizations (including our own) will die out before producing trillions of people.

II. The Devil’s Existence

The Devil’s Existence (DE) is a thought experiment where you are asked to determine whether or not the Devil exists (the Devil representing some doom event).
Suppose God creates 1 million rooms, each sequentially numbered, and that He initially intends to fill each room with one person.
He first goes to room 1 and generates a person inside.
He then moves on to room 2 and does the same, and so on, until the first 10 rooms have been filled.
At this point, if and only if the Devil exists, he arrives on the scene and destroys the remaining rooms so that no more people are created.
Suppose you have been created and find yourself in room 7.
Assuming you thought it equally likely that the Devil does or does not exist before
considering this information, how likely is it now that the Devil exists? …..
(….)

Conclusion
Consider our current circumstance: we exist in a civilization that has produced only 70 billion people.
At first sight, our data seems highly unlikely.
If our civilization dies out soon so that it is ultimately small, then not that many people exist and it is highly unlikely that you and I are alive.
If our civilization is ultimately very, very large, then our existence might be explained, but it is highly unlikely for you and I to have such low birth numbers.
Given the situation, we can either accept that we are atypical or we can seek plausible alternative theories that better explain our data.
Here, I have considered the following theory: there are many, many civilizations that exist and nearly all of these civilizations are small.
Under this theory, our existence is certain and our birth number is typical.
Because the theory makes our circumstance likely and alternatives do not, we should drastically increase our belief that the theory is true when conditioning on our data.
Read more: arxiv.org/pdf (http://arxiv.org/abs/1209.6251)

Written by physicsgg

September 28, 2012 at 7:25 pm

Posted in COSMOLOGY, philosophy

Brian Greene: Welcome to the Multiverse

with one comment

The latest developments in cosmology point toward the possibility that our universe is merely one of billions.

“What really interests me is whether God had any choice in creating the world.”

That’s how Albert Einstein, in his characteristically poetic way, asked whether our universe is the only possible universe.
The reference to God is easily misread, as Einstein’s question wasn’t theological. Instead, Einstein wanted to know whether the laws of physics necessarily yield a unique universe—ours—filled with galaxies, stars, and planets. Or instead, like each year’s assortment of new cars on the dealer’s lot, could the laws allow for universes with a wide range of different features? And if so, is the majestic reality we’ve come to know—through powerful telescopes and mammoth particle colliders—the product of some random process, a cosmic roll of the dice that selected our features from a menu of possibilities? Or is there a deeper explanation for why things are the way they are?

In Einstein’s day, the possibility that our universe could have turned out differently was a mind-bender that physicists might have bandied about long after the day’s more serious research was done. But recently, the question has shifted from the outskirts of physics to the mainstream. And rather than merely imagining that our universe might have had different properties, proponents of three independent developments now suggest that there are other universes, separate from ours, most made from different kinds of particles and governed by different forces, populating an astoundingly vast cosmos.

The multiverse, as this vast cosmos is called, is one of the most polarizing concepts to have emerged from physics in decades, inspiring heated arguments between those who propose that it is the next phase in our understanding of reality, and those who claim that it is utter nonsense, a travesty born of theoreticians letting their imaginations run wild.

So which is it? And why should we care? Grasping the answer requires that we first come to grips with the big bang…..
Read more: www.thedailybeast.com

Written by physicsgg

May 23, 2012 at 4:58 am

Posted in COSMOLOGY, philosophy

Tagged with

Has Physics Made Philosophy and Religion Obsolete?

with one comment

“I think at some point you need to provoke people. Science is meant to make people uncomfortable.”

It is hard to know how our future descendants will regard the little sliver of history that we live in. It is hard to know what events will seem important to them, what the narrative of now will look like to the twenty-fifth century mind. We tend to think of our time as one uniquely shaped by the advance of technology, but more and more I suspect that this will be remembered as an age of cosmology—as the moment when the human mind first internalized the cosmos that gave rise to it. Over the past century, since the discovery that our universe is expanding, science has quietly begun to sketch the structure of the entire cosmos, extending its explanatory powers across a hundred billion galaxies, to the dawn of space and time itself. It is breathtaking to consider how quickly we have come to understand the basics of everything from star formation to galaxy formation to universe formation. And now, equipped with the predictive power of quantum physics, theoretical physicists are beginning to push even further, into new universes and new physics, into controversies once thought to be squarely within the domain of theology or philosophy.

In January, Lawrence Krauss, a theoretical physicist and Director of the Origins Institute at Arizona State University, published A Universe From Nothing: Why There Is Something Rather Than Nothing, a book that, as its title suggests, purports to explain how something—and not just any something, but the entire universe—could have emerged from nothing, the kind of nothing implicated by quantum field theory. But before attempting to do so, the book first tells the story of modern cosmology, whipping its way through the big bang to microwave background radiation and the discovery of dark energy. It’s a story that Krauss is well positioned to tell; in recent years he has emerged as an unusually gifted explainer of astrophysics. One of his lectures has been viewed over a million times on YouTube and his cultural reach extends to some unlikely places—last year Miley Cyrus came under fire when she tweeted a quote from Krauss that some Christians found offensive. Krauss’ book quickly became a bestseller, drawing raves from popular atheists like Sam Harris and Richard Dawkins, the latter of which even compared it to The Origin of Species for the way its final chapters were supposed to finally upend “last trump card of the theologian.”….
Read more: www.theatlantic.com/technology

Written by physicsgg

April 24, 2012 at 12:39 pm

Posted in COSMOLOGY, philosophy

Tagged with

Video: The Most Astounding Fact

leave a comment »

Astrophysicist Dr. Neil DeGrasse Tyson was asked by a reader of TIME magazine, “What is the most astounding fact you can share with us about the Universe?” This is his answer. (subtitles: click CC)


http://youtu.be/9D05ej8u-gU

Written by physicsgg

March 6, 2012 at 6:38 pm

The Relativity of Existence

leave a comment »

Despite the success of physics in formulating mathematical theories that can predict the outcome of experiments, we have made remarkably little progress towards answering some of the most basic questions about our existence, such as:
why does the universe exist?
Why is the universe apparently fine-tuned to be able to support life?
Why are the laws of physics so elegant?
Why do we have three dimensions of space and one of time? How is it that the universe can be non-local and non-causal at the quantum scale, and why is there quantum randomness?
In this paper, it is shown that all of these questions are answered if existence is relative, and moreover, it seems that we are logically bound to accept it……
Read more: http://arxiv.org/pdf

Written by physicsgg

February 24, 2012 at 5:05 pm