Physics Quiz: Standard Model Answers

by Eric Drexler on 2014/04/19

Last week’s Physics Quiz asked about errors in Wikipedia’s current diagram of the Standard Model.

Here’s the diagram with corrections; answers follow:

  1. What do the arcs represent?
    • The Standard Model interactions between particles: the boson-mediated strong, weak, and electromagnetic forces.
  2. Which of the arcs is incorrect? [And a question that got lost: Where is an arc is missing?]
    • The arc linking charged and uncharged leptons is spurious: It does not represent a force.
    • The arc representing the Higgs-neutrino interaction was omitted (see also #4).
  3. Extra credit, Wikipedia history department:
      How did one correction lead to both errors?
    • Neutrinos had been lumped together with the charged leptons, wrongly suggesting that all leptons interact with photons; when they were split off in the current diagram, the two classes of leptons were linked by the spurious arc, while neutrinos lost their link to the Higgs.
  4. Where is a second arc missing?
    • The Z boson interacts with other Z bosons via the weak force, paralleling interactions between W bosons; this arc is missing.

Note that the Z boson is, from a practical point of view, a leading candidate for the most useless particle in the Standard Model. They’re crucial for neutrino-neutrino scattering, of course, as if anyone really cared.


Physics Quiz: The Standard Model

by Eric Drexler on 2014/04/16

The Wikipedia page on the Standard Model currently includes the diagram below:

  1. What do the arcs represent?
  2. Which of the arcs is incorrect?
  3. Extra credit, Wikipedia history department:
      How did one correction lead to both errors?
  4. Added: Where is a second arc missing? (This makes question 3 ambiguous.)

17 April update: added question 4 after contemplating weak interactions and checking the literature

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The five kinds of nanotechnology

by Eric Drexler on 2014/04/04

Why understanding seems stuck:

I count five kinds of nanotechnology, of which only three are called by that name. Of the three, one is a revolutionary prospect, one is a fantasy, and the third is mostly materials science. As for the other two kinds, one is the heart of today’s greatest technological revolution, while the other is the basis for progress toward the revolutionary prospect — but neither of these is called “nanotechnology”.

This may seem confusing, and it is. Indeed, people who think they know something about “nanotechnology” often have a lot to unlearn, and would be better off knowing basic physics and chemistry and starting from there. This situation makes it extraordinarily difficult to have a productive conversation about what really matters.

Here’s a compact summary in a nice, legible png image:

Please copy or link the above wherever it might surprise someone:
<img src="">


Rise of the robots (per the Economist)

by Eric Drexler on 2014/04/01

In the Economist: “Rise of the robots: Prepare for a robot invasion. It will change the way people think about technology”.

The robotics revolution is, of course, riding the exponential wave of today’s leading nanotechnology, digital nanoelectronics, and today’s robots give only a taste of what nanomechanical technologies will enable through radical improvements in the cost and performance of physical products.

We really need to think about the real future — how to manage a world with pervasive robotics, pervasive surveillance, and radical material abundance (there’s a book about that).


The end of the thermodynamics of computation?

by Eric Drexler on 2014/03/29

In a recent post, the always intelligent and provocative Cosma Shalizi notes John D. Norton’s argument against (nearly) thermodynamically reversible computation, but Norton’s argument is mistaken.

In his paper “The End of the Thermodynamics of Computation: A No-Go Result,” Norton correctly states that “In a [nearly] thermodynamically reversible process, all component systems are in [nearly] perfect equilibrium with one another at all stages,” and then discusses systems in which “Fluctuations will carry the system spontaneously from one stage to another [and as] a result, the system is probabilistically distributed over the different stages.”

But the stages of computation themselves need not be in equilibrium with one another, and hence subject to back-and-forth fluctuations. Instead, a time-varying potential can carry a system deterministically through a series of stages while the system remains at nearly perfect thermodynamic equilibrium at each stage. In other words, the state of the system need not be probabilistically distributed over the different stages.

This is an example of a scientist describing an unworkable solution to a problem and then asserting that no solution will work, when workable solutions are already known. Richard Smalley did a similar but more damaging disservice to atomically precise fabrication by inventing and rejecting an unworkable concept involving exotic atom-plucking “fingers,” while ignoring a decades-old literature that described the now-mundane concept of guiding the motion of reactive molecules.

TL;DR: The standard view of the thermodynamics of computation is correct.


Civilizational impact

by Eric Drexler on 2014/03/13

Nanoelectronics is a nanotechnology that makes possible the drone technologies that threaten to upend the power relationships that underpin modern civilization:

Drones will cause an upheaval of society like we haven’t seen in 700 years

Noah Smith is often worth reading:


Environmental Impact

March 5, 2014

From xkcd. How to roll back the impact of agriculture here.

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Speaking in Colorado at two Curiosity Retreats

March 4, 2014

John Hendricks founded the Discovery Channel and Discovery Communications, aiming to change the way people think about science and the world around them. The Curiosity Project, is his new, personally funded venture to bring audiences “deep dive” content in science, technology, and broader areas of human concern. I will be speaking at the two inaugural […]

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Apologies for Oxford talk overflow

January 25, 2014

My apologies to readers who were turned away from my Oxford talk on Radical Abundance last Wednesday — the room had reached capacity.

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Talk at Oxford: “Remaking the 21st Century”

January 21, 2014

I’m giving a talk for the Oxford University Scientific Society this Thursday, January 23rd. See announcement: Dr Eric Drexler: “Remaking the 21st Century” (Thursday, in the Lindemann Lecture Theatre, Clarendon Lab) 23/1, 8:15 pm. Note also my Oxford book event tomorrow, January 22nd. (Previous post here.)

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Book talk at Oxford

December 10, 2013

I will be giving a book talk hosted by the Oxford Martin School and the Oxford Martin Programme on the Impacts of Future Technology. Reception follows. Radical abundance: How a revolution in nanotechnology will change civilization 22 January 2014 17:00 – 18:30 Oxford Martin School 34 Broad Street (corner of Holywell and Catte Streets) Oxford […]

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Radical Abundance featured in the Times Literary Supplement

December 9, 2013

See note and link here.

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