1-dan master of the unyielding fist of Bayesian inference
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PDQP/qpoly = ALL

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I’ve put up a new paper.  Unusually for me these days, it’s a very short and simple one (8 pages)—I should do more like this!  Here’s the abstract:

    We show that combining two different hypothetical enhancements to quantum computation—namely, quantum advice and non-collapsing measurements—would let a quantum computer solve any decision problem whatsoever in polynomial time, even though neither enhancement yields extravagant power by itself. This complements a related result due to Raz. The proof uses locally decodable codes.

I welcome discussion in the comments.  The real purpose of this post is simply to fulfill a request by James Gallagher, in the comments of my Robin Hanson post:

The probably last chance for humanity involves science progressing, can you apply your efforts to quantum computers, which is your expertise, and stop wasting many hours of you [sic] time with this [expletive deleted]

Indeed, I just returned to Tel Aviv, for the very tail end of my sabbatical, from a weeklong visit to Google’s quantum computing group in LA.  While we mourned tragedies—multiple members of the quantum computing community lost loved ones in recent weeks—it was great to be among so many friends, and great to talk and think for once about actual progress that’s happening in the world, as opposed to people saying mean things on Twitter.  Skipping over its plans to build a 49-qubit chip, Google is now going straight for 72 qubits.  And we now have some viable things that one can do, or try to do, with such a chip, beyond simply proving quantum supremacy—I’ll say more about that in subsequent posts.

Anyway, besides discussing this progress, the other highlight of my trip was going from LA to Santa Barbara on the back of Google physicist Sergio Boixo’s motorcycle—weaving in and out of rush-hour traffic, the tightness of my grip the only thing preventing me from flying out onto the freeway.  I’m glad to have tried it once, and probably won’t be repeating it.

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clumma
5 days ago
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Berkeley, CA
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Deep State Update

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It's been clear for well over a year now that the Obama DOJ-FBI-CIA used massive surveillance powers (FISA warrant, and before that, national security letters and illegal contractor access to intelligence data) against the Trump campaign. In addition to SIGINT (signals intelligence, such as email or phone intercepts), we now know that HUMINT (spies, informants) methods were also used. Until
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clumma
8 days ago
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Berkeley, CA
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The Upside, A5, Pen on Paper

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The Upside, A5, Pen on Paper submitted by /u/Awhyuss to r/Art
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clumma
9 days ago
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Berkeley, CA
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Per capita VMT is peaking out...again

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US vehicle miles traveled posted an outright loss of 0.1% year on year for February 2018.  This was the first annual decline since early 2014, when oil prices averaged over $100 / barrel.

US VMT.jpg

Of greater concern is the peaking out of per capita vehicle miles driven, which occurred in August 2017.  Since then, VMT per capita has plateaued and in fact fallen every month since November last year.  

Although oil prices have been rising, they were not particularly high at the last November -- under $50 / barrel, actually.  Thus, the decline in per capita VMT is difficult to attribute solely to rising oil prices.  Nor can it easily be attributed to the economy, which has performed very well in recent quarters.  The more plausible explanation is a demographic shift, with seniors representing a larger share of the non-institutional, aged 16+ population which forms the demographic basis of our analysis.  Old people drive less.

Put another way, US society is beginning to age out to all appearances.  

This matters because GDP and VMT have long been highly correlated.  If VMT per capita is peaking out, then achieving GDP growth rates much above 2% also looks problematic.  

Form a political point of view, it suggests a society becoming increasingly conservative and brittle.  We are beginning to look more like Japan.  

From an infrastructure perspective, drivers are behind the wheel in the equivalent of 19 fewer days per year than they were in 2005.  And that looks to deteriorate from here on out.  Demands on transportation infrastructure may be peaking.

Not a comforting picture, really.

Per Cap VMT.png
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clumma
12 days ago
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Russian under US sanctions refuses to resign as world chess head

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Russian under US sanctions refuses to resign as world chess head submitted by /u/dengorilla1 to r/chess
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clumma
12 days ago
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Berkeley, CA
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Oil Consumption as a Percent of World GDP

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When oil is cheap and oil spend is less than 2.5% of world GDP, the global economy tends to grow at a solid pace. 

When oil consumption exceeds 4.5% of global GDP, the world economy typically faces either recession or stagnation (in the 1970s, 'stagflation', after 2011, 'secular stagnation').  

In between, when oil consumption exceeds 2.25%, but is less than 4.5%, of GDP, growth can continue, but oil prices begin to weigh on the economy.  Interestingly, oil prices are not stable in this 'no man's land'.  That is, the demand-constrained price of oil is 1.75-2.5% of GDP; the supply-constrained price of oil is above 4.5%.  The oil price will either fall to the demand-constrained price or rise to the supply-constrained price.  There is no stable landing point in between.

OIl as a Percent of Global GDP.png

Oil prices have moved back into 'no man's land' and are no longer cheap.  The futures curve still believes oil prices will be demand-constrained in the 2020s, but given the extraordinary dependence of global demand growth on an ever-increasing Permian supply, the odds of it ending badly look high.

Our outlook now anticipates that the current business cycle will end in 2021 with oil spend averaging 5.1% of GDP for the year, representing an average price of $138 / barrel on a Brent basis.

Whether the price spikes higher depends on whether the advanced economies revert to 'fight' rather than 'flight' mode.  In fight mode, as we saw from 2005 to 2008, the advanced economies were willing to enter into a bidding war with China for incremental barrels, a contest which the advanced economies were destined to lose.  

This same competition emerged during the Arab Spring in 2011, with oil prices staying high thereafter, but never again reaching the $147 / barrel price seen briefly in 2008.  Instead, the advanced economies consistently yielded oil consumption to emerging markets and were ground down in flight mode, with oil generally in the $100-115 / barrel range until the shale revolution tanked oil prices in 2014.

On balance, a resumption of grinding oil prices seems more likely, which would take peak oil prices for this cycle (which started in H2 2014) above $130 / barrel, but probably not to the $200 / barrel price we would see were animal spirits to revive in the advanced economies or the global oil supply materially disrupted.

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clumma
12 days ago
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