Monday, September 27, 2021

Motion through the Restframe of the Universe

A lot of people think that the essence of relativity is that there is no rest frame, and no way to say that an object is at rest. This is not true. There is a preferred rest frame for the universe.

Dr. Bee explains it in her weekly podcast:

If the universe expands the same everywhere, then doesn’t this define a frame of absolute rest. Think back of that elastic band again. If you sit on one of the buttons, then you move “with the expansion of the universe” in some sense. It seems fair to say that this would correspond to zero velocity. But didn’t Einstein say that velocities are relative, and that you’re not supposed to talk about absolute velocities. I mean, that’s why it’s called “relativity” right? Well, yes and no.

If you remember, Einstein really had two theories, first special relativity and then general relativity. Special relativity is the theory in which there is no such thing as absolute rest and you can only talk about relative velocities. But this theory does not contain gravity, which Einstein described as the curvature of space and time. If you want to describe gravity and the expansion of the universe, then you need to use general relativity.

In general relativity, matter, or all kinds of energy really, affect the geometry of space and time. And so, in the presence of matter the universe indeed gets a preferred direction of expansion. And you can be in rest with the universe. This state of rest is usually called the “co-moving frame”, so that’s the reference frame that moves with the universe. This doesn’t disagree with Einstein at all.

What is the co-moving frame of the universe? It’s normally assumed to be the same as the rest frame of the cosmic microwave background, or at least very similar to it. So what you can do is you measure the radiation of the cosmic microwave background that is coming at us from all directions. If we were in rest with the cosmic microwave background, the energy in that radiation should be the same in all directions. This isn’t the case though, instead we see that the radiation has somewhat more energy in one particular direction and less energy in the exact opposite direction. This can be attributed to our motion through the restframe of the universe.

How fast do we move? Well, we move in many ways, because the earth is spinning and orbiting around the sun which is orbiting around the center of the milky way. So really our direction constantly changes. But the Milky Way itself moves at about 630 kilometers per second relative to the cosmic microwave background. That’s about a million miles per hour. Where are we going? We’re moving towards something called “the great attractor” and no one has any idea what that is or why we’re going there.

Relativity teaches that there is a symmetry transformation from one inertial frame to another. The laws of electromagnetism and other physics are transformed by covariance. But there can still be something that distinguishes a frame as being at rest, and that something is the cosmic microwave background radiation.

Friday, September 24, 2021

SciAm on Politically Correct Acronyms

Scientific American magazine used to be outstanding. Subscribers would save every issue as if they were treasured books.

Now it publishes this political essay that appears to be a joke, but is not:

Why the Term ‘JEDI’ Is Problematic for Describing Programs That Promote Justice, Equity, Diversity and Inclusion

They’re meant to be heroes within the Star Wars universe, but the Jedi are inappropriate symbols for justice work

The acronym “JEDI” has become a popular term for branding academic committees and labeling STEMM (science, technology, engineering, mathematics and medicine) initiatives focused on social justice issues. Used in this context, JEDI stands for “justice, equity, diversity and inclusion.” In recent years, this acronym has been employed by a growing number of prominent institutions and organizations, including the National Academies of Sciences, Engineering, and Medicine. At first glance, JEDI may simply appear to be an elegant way to explicitly build “justice” into the more common formula of “DEI” (an abbreviation for “diversity, equity and inclusion”), productively shifting our ethical focus in the process. JEDI has these important affordances but also inherits another notable set of meanings: It shares a name with the superheroic protagonists of the science fiction Star Wars franchise, the “Jedi.” Within the narrative world of Star Wars, to be a member of the Jedi is seemingly to be a paragon of goodness, a principled guardian of order and protector of the innocent.

The Jedi are inappropriate mascots for social justice. Although they’re ostensibly heroes within the Star Wars universe, the Jedi are inappropriate symbols for justice work. They are a religious order of intergalactic police-monks, prone to (white) saviorism and toxically masculine approaches to conflict resolution (violent duels with phallic lightsabers, gaslighting by means of “Jedi mind tricks,” etc.). The Jedi are also an exclusionary cult, membership to which is partly predicated on the possession of heightened psychic and physical abilities (or “Force-sensitivity”). Strikingly, Force-wielding talents are narratively explained in Star Wars not merely in spiritual terms but also in ableist and eugenic ones: These supernatural powers are naturalized as biological, hereditary attributes. ...

This is an opinion and analysis article; the views expressed by the author or authors are not necessarily those of Scientific American.

If I didn't know better, I would say that SciAm is gaslighting us with a Jedi mind trick.

Update: Scott Aaronson writes:

The sad thing is, I see few signs that this essay was meant as a Sokal-style parody, although in many ways it’s written as one. The essay actually develops a 100% cogent, reasoned argument: namely, that the ideology of the Star Wars films doesn’t easily fit with the newer ideology of “militant egalitarianism at the expense of all other human values, including irony, humor, joy, and the nurturing of unusual talents.” The authors are merely oblivious to the conclusion that most people would draw from their argument: namely, so much the worse for the militant egalitarianism then!
He then relates this to his favorite bugaboos -- feminists belittling his nerdishness, and how the supposedly authoritarian Donald Trump is taking over the world. Sometimes I wonder if Scott is trolling us.

Wednesday, September 22, 2021

Rovelli Defends his Favorite QM Interpretation

Physicist Carlo Rovelli has written a defense of The Relational Interpretation of Quantum Physics:
Relational QM is a radical attempt to cash out the breakthrough that originated the theory: the world is described by facts described by values of variables that obey the equations of classical mechanics, but products of these variable have a tiny non-commutativity that generically prevents sharp value assignment, leading to discreteness, probability and to the contextual, relational character of value assignment.

The founders expressed this contextual character on Nature in the “observer- measurement” language. This language requires that special systems (the ob- server, the classical world, macroscopic objects...) escape the quantum limi- tations. But nothing of that sort (and in particular no “subjective states of conscious observers”) is needed in the interpretation of QM. We can relinquish this exception, and realise that any physical system can play the role of a Copenhagen’s “observer”. Relational QM is Copenhagen quantum mechanics made democratic by bringing all systems onto the same footing. Macroscopic observers, that loose information to decoherence, can forget the labelling of facts.

Go ahead and read the 20 pages if you want, but I will save you some trouble. It is pretty much the same as the Copenhagen Interpretation that you find in textbooks.

Apparently it bugs him that some descriptions of Copenhagen refer to a conscious observer, and that offends him, so he just calls everything an observre and doesn't care if it is conscious or not. If it is not consicous, then it may not figure out what the wave function is supposed to be, but it doesn't have to match anyone else's wave function, so nobody cares.

Thursday, September 16, 2021

Google Promises a Usable Quantum Computer in 2029

The WSJ reported a couple of months ago:
Google scientist Hartmut Neven said the company intends to invest several billion dollars to build a commercial-grade quantum computer that can perform large-scale, error-free business and scientific calculations by 2029.

Google's Sundar Pichai announced the project's timeline, and unveiled the new Google Quantum Artificial Intelligence (AI) campus in Santa Barbara County, CA, to develop the system.

The Internet search giant aims to deliver commercial-grade quantum-computing services over the cloud, while Neven said the company envisions applications ranging from building more energy-efficient batteries to accelerating training for machine learning AI.

Google said such applications will require a 1-million-quantum bit (qubit) computer.

Neven said one of the technical challenges will be to extend the length of time that a qubit can remain in its quantum state.

I doubt it, but this blog may not still be watching the issue in 2029.

This sounds like an impressive Google commitment, but there is a very long list of Google ambitions that have been abandoned. See Killed by Google for a list of 240 of them.

I got this article from the top US computer scientist association, and I see that they are gone anti-White in another article:

In June 2020, a community of Black people in computing from around the world published an open letter,a initiated by the authors, and a call for actionb to the global computing community. The letter began with, "The recent killing of George Floyd by Minneapolis Police has sparked a movement that began at the birth of our nation. Though George Floyd may have been the most recent instance, we should not forget the lives of Breonna Taylor, Ahmaud Arbery, Nina Pop, Tony McDade, Sandra Bland, Trayvon Martin, Aiyana Stanley-Jones, Philando Castille, Tanisha Anderson, Atatiana Jefferson, Eric Garner, Charleena Lyles, Eula Love, Michael Brown, Khalif Browder, Botham Jean, Tamir Rice, Latasha Harlins, Amadou Diallo, Mary Turner, Emmett Till, and too many other Black people who have been murdered …"

At the time, we reflected on this history of the killing of Black people in the U.S. and noted that these killings not only show the ultimate outcomes and harms that racist systems and institutions have on Black people, but they also spotlight the constant emotional and psychological strain that Black Americans endure. The accumulated experience of the Black computer science community highlights the magnitude of injustices that countless members of our community experience.

No, this is nonsense. I watched the Trayvon Martin trial on TV, and it was convincingly proved that he was not murdered. I watched the George Floyd trial also, and no evidence was even presented that race had anything to do with his death. If anything, the stories of George Floyd and others spotlight the constant strain Black felons and junkies put on our society.
Today, we are issuing another call to action to the individuals, organizations, educational institutions, and companies in the computing ecosystem to address the systemic and structural inequities
The ACM has no business raising these issues, but since it is demanding that these issues be addressed, I should say that it is all a big hoax, and that all of the racism is to the benefit of Blacks.

Officially, the US NSA is not worried about quantum computers:

Q: Is NSA worried about the threat posed by a potential quantum computer because a CRQC exists?

A: NSA does not know when or even if a quantum computer of sufficient size and power to exploit public key cryptography (a CRQC) will exist.

And it is negative about quantum key distribution:
Q: Are QKD systems unconditionally secure?

A: No. While there are security proofs for theoretical QKD protocols, there are no security proofs for actual QKD hardware/software implementations. There is no standard methodology to test QKD hardware, and there are no established interoperability, implementation, or certification standards to which these devices may be built. This causes the actual security of particular systems to be difficult to quantify, leading in some cases to vulnerabilities.

Q: Should I use a QKD system to protect my NSS from a quantum computer?

A: No. The technology involved is of significant scientific interest, but it only addresses some security threats and it requires significant engineering modifications to NSS communications systems. NSA does not consider QKD a practical security solution for protecting national security information.

This seems right to me. I have posted here many times that QKD has no practical value, despite the many millions going into it, and the proponent claims that it is the only provably secure cryptography.

The NSA looks 20 years ahead, and is keeping tabs on progress in quantum computers, and in defending against them. If it really htought that Google would have a commercial quantum computer with a million qubits in 2029, then it would be already converting to a quantum-resistant cryptography. Based on this FAQ, it see a quantum computer as speculative, and in the distant future, if at all.

Monday, September 13, 2021

Mathematicians Agree on the Fundamentals

It is commonly remarked that mathematicians agree on fundamental questions, but a philosopher disagrees:
Mathematical and Moral Disagreement
Silvia Jonas

The existence of fundamental moral disagreements is a central problem for moral realism and has often been contrasted with an alleged absence of disagreement in mathematics. However, mathematicians do in fact disagree on fundamental questions, for example on which set-theoretic axioms are true, and some philosophers have argued that this increases the plausibility of moral vis-à-vis mathematical realism.

She finds some minor disagreements, but only support the idea that they agree on the fundamentals.

She finds that mathematicians broadly agree on ZFC and first order logic as a suitable axiomitization of set theory and mathematics. The disagreements are about how much constructive proofs are to be preferred to nonconstructive ones, and the value of adding axioms to ZFC. Some regard the continuum hypothesis as a settled issue, while others look for new axioms to settle it.

This is like saying Democrats don't agree on whether to spend $3.5T or $3.6T.

These disagreements do not even affect what is publishable and what is not.

Wrong proofs do get published sometimes. Scott Aaronson

publicly confesses to his:

Continuing what’s become a Shtetl-Optimized tradition—see here from 2014, here from 2016, here from 2017 — I’m going to fess up to two serious mistakes in research papers on which I was a coauthor.
I am surprised that so many serious errors made it past the editors and referees, but that is just sloppiness, and not any disagreement over fundamentals.

Here is a YouTube panel discussion on Does Math Reveal Reality? Unfortunately, physicists do most of the talking. At 1:22:00, cosmologist Max Tegmark says;

That's right, they call that the Level 4 Multiverse.

So when we talk about something existing if we say pink elephants don't exist, what we secretly tend to mean by that is while don't exist here on Earth or anywhere where we've looked, but maybe there is another planet really really far away where you actually have pink elephants.

No, that is not what I mean by pink elephants not existing. Tegmark denies that you can ever talk about hypothetical or counterfactual objects. He says that if you can talk about it, then it exists in some parallel or distant universe.

Tuesday, September 7, 2021

Hsu Paper on Finitism and Physics

Professor Steve Hsu is a physicist, but is known better for trying to use genomics to better the human condition. He writes in a new paper:
Our intuitions about the existence and nature of a continuum arise from perceptions of space and time [21]. But the existence of a fundamental Planck length suggests that spacetime may not be a continuum. In that case, our intuitions originate from something (an idealization) that is not actu ally realized in Nature.

Quantum mechanics is formulated using continuous structures such as Hilbert space and a smoothly varying wavefunction, incorporating complex numbers of arbitrary precision. However beautiful these structures may be, it is possible that they are idealizations that do not exist in the physical world.

I would go further and say that probability does not exist in the physical world.
It may come as a surprise to physicists that infinity and the continuum are even today the subject of debate in mathematics and the philosophy of mathematics. Some mathematicians, called finitists, accept only finite mathematical objects and procedures [25]. The fact that physics does not require infinity or a continuum is an important empirical input to the debate over finitism.
Yes, but it is hard to prove much unless you assume mathematical infinities.

It is important to realize that the infinities are mathematical abstractions, and natural observations are all finite.

There was a concerted effort beginning in the 20th century to place infinity and the continuum on a rigorous foundation using logic and set theory. However, these efforts have not been successful. For example, the standard axioms of Zermelo-Fraenkel (ZFC) set theory applied to infinite sets lead to many counterintuitive results such as the Banach-Tarski Paradox: given any two solid objects, the cut pieces of either one can be reassembled into the other [23].
No, this is wrong. ZFC is a perfectly foundation for mathematics, and is widely accepted. Those Banach-Tarski subsets are not measurable, and do not undermine ZFC.
Post-Godel there is no general agreement as to what is meant by "rigorous foundations"...

No, this is a common misconception. Mathematics was on shaky foundations in the 1800s. Basic concepts like real numbers and sets had not been rigorously defined. Goedel helped show that first order logic had the properties that mathematicians needed, and helped prove that axiomatizations of set theory could be used for foundations. Soon mathematician settled on ZFC as a suitable foundation for all of mathematics.