Thursday, August 25, 2022

Harvard Veritas: interview with a recent graduate (anonymous) — Manifold Episode #18


The guest for this episode is a recent graduate of Harvard College, now pursuing a STEM PhD at another elite university. We have withheld his identity so that he can speak candidly. 

Steve and his guest discuss: 

0:00 Anonymous student’s academic background and admission to Harvard 
21:37 Intellectual curiosity at Harvard 
29:36 Academic rigor at Harvard and the difference between classes in STEM and the humanities 
46:47 Access to tenured professors at Harvard 
50:08 The benefits of the Harvard connection and wider pool of opportunities 
58:46 Competing with off-scale students 
1:00:48 Ideological climate on campus, wokeism, and controversial public speakers 
1:23:11 Dating at Harvard 
1:26:52 Z-scores and other metrics to add to the admissions process 

Harvard Admissions and Meritocracy: 

From first link above, The Chosen by J. Karabel.

Typology used for all applicants, at least as late as 1988: 

1. S First-rate scholar in Harvard departmental terms. 

2. D Candidate's primary strength is his academic strength, but it doesn't look strong enough to quality as an S (above). 

3. A All-Amercan‚ healthy, uncomplicated athletic strengths and style, perhaps some extracurricular participation, but not combined with top academic credentials. 

4. W Mr. School‚ significant extracurricular and perhaps (but not necessarily) athletic participation plus excellent academic record. 

5. X Cross-country style‚ steady man who plugs and plugs and plugs, won't quit when most others would. Gets results largely through stamina and consistent effort. 

6. P PBH [Phillips Brooks House] style: in activities and personal concerns. 

7. C Creative in music, art, writing. 

8. B Boondocker‚ unsophisticated rural background. 

9. T Taconic, culturally depressed background, low income. 

10. K Krunch‚ main strength is athletic, prospective varsity athlete. [ Sometimes also "H Horse" :-) ] 

11. L Lineage‚ candidate probably couldn't be admitted without the extra plus of being a Harvard son, a faculty son, or a local boy with ties to the university community. 

12. O Other‚ use when none of the above are applicable.

Friday, August 19, 2022

Geostrategy and US-China Military Competition

I've been asked to write something about PRC military buildup and a potential Taiwan (TW) conflict. 

1. My perspective and bona fides: My father was a KMT officer, my mother's father was a KMT general and that side of the family is related to Chiang Kai Shek by marriage. I have relatives both in PRC and TW. My wife is a graduate of National Taiwan University. I should be biased in favor of TW and against CPC but I am a realist and rationalist so I call things as I see them. 

2. PRC military technology has reached parity with the US and, overall, surpassed Russia. PLARF (dedicated rocket forces) may be decisive in a conflict in the pacific. They may have achieved A2AD and can make it very costly for the US navy to operate anywhere near TW. 

3. Specifically, long range missile attack on surface ships, using initial targeting via satellites and drones, and final targeting from sensors on the missile itself, is probably a mature technology now and difficult to defeat with countermeasures / missile defense. 

4. US estimates of PRC nuclear weapons stockpile have barely changed in 30y and are likely highly unreliable. Based on production capabilities alone they may already have ~1000 warheads (if not now, in a few years), and the ability to target the entire US. PRC is building up its arsenal to ensure that the US understands that they have a reliable MAD capability. 

5. PRC can easily blockade TW if desired, and (at cost of significant escalation) can probably also blockade Japan and S. Korea as well. All of these countries import ~90% of energy and ~50% of food calories, so a protracted blockade would have serious impact. 

6. I don’t believe PRC has near term plans to invade TW, but they have to maintain the capability to deter any change in the status quo. Both sides prefer the status quo but accidents can happen. 

7. Thanks to stupid US strategy re: Ukraine, PRC can rely on Russian energy in the future and will become much more resistant to naval blockade (e.g., of oil supplies transiting the Malacca Strait). In other words, dumb US neocons solved PRC’s energy security problem for them. 

No one talks about this because US strategy has been brain dead for a long time. No one even talks, in the immediate aftermath, about the trillions of dollars and millions of lives wasted over 20y in the Iraq/Afghanistan tragedies. Cui bono?

8. PRC spends a smaller fraction of GDP on defense than the US, but because they have mastered the entire military technology stack cost estimates should be PPP adjusted. After PPP adjustment the PRC economy is substantially larger than the US economy. This, plus the fact that their manufacturing capacity (e.g., ship building) is far beyond that of the US, means that their overall capability to produce war materiel (i.e., to engage in a rapid buildup on, e.g., a 5y timescale) has easily surpassed ours. Anyone following their recent naval or air power or missile or satellite build up can see that this is the case.

I'll be discussing some of these topics with Lyle Goldstein (US Naval War College, Watson China Initiative at Brown University; BA Harvard, PhD Princeton) in a future podcast.

See also this documentary produced by the US Army University Press. Queued to start at discussion of missile technology and nuclear weapons.



Panic bells, it's red alert 
There's something here from somewhere else 
The war machine springs to life 
Opens up one eager eye 
Focusing it on the sky 
-- 99 Luftballons

Sunday, August 14, 2022

Tweet Treats: AI in PRC, Semiconductors and the Russian War Machine, Wordcels are Midwits

Some recent tweets which might be of interest :-)

Thursday, August 11, 2022

Manifold Episode #18

You may have noticed the post earlier today about the episode with Amy Chua of Yale Law School. That episode has been removed by request of Amy's publisher. Her new book is not out until 2023 and she has been asked not to do any media until then. 

Wednesday, August 03, 2022

A Brief History of Hawking's Information Paradox (European Physics Letters)

This is a short review of our recent work on black hole information for European Physics Letters.
A Brief History of Hawking's Information Paradox 

European Physics Letters 139 (2022) 49001

Xavier Calmet and Stephen D. H. Hsu 

In this invited review, we describe Hawking's information paradox and a recently proposed resolution of it. Explicit calculations demonstrate the existence of quantum hair on black holes, meaning that the quantum state of the external graviton field depends on the internal state of the black hole. Simple quantum mechanics then implies that Hawking radiation amplitudes depend on the internal state, resulting in a pure final radiation state that preserves unitarity and, importantly, violates a factorization assumption which is central to the original paradox. Black hole information is encoded in entangled macroscopic superposition states of the radiation. 

DOI: 10.1209/0295-5075/ac81e8

From Conclusions:
... The radiation amplitudes computed by Hawking, which describe thermal radiation emitted from a black hole at temperature T, already describe a broad distribution of possible radiation types, spins, and momenta emitted at each stage. Thus, even in the semiclassical approximation there are many distinct patterns of radiation in (6). The set of possible final states is already complex even at leading order, resulting in very different coarse grained patterns of energy-momentum density. Small corrections to the amplitudes α(E, r) due to quantum hair do not qualitatively change this situation, but they are necessary to unitarize the evaporation and they determine the precise relations between components of the entangled state. 
Importantly, no special assumptions about the amplitudes α(E, r) need to be made to determine that the factorized form of the state (2) does not hold. Factorization is assumed in essentially every formulation of the information paradox, but in reality is violated because the external graviton state depends on the internal black hole state. 
Known quantum gravitational effects leading to quantum hair are extremely small and thus difficult to probe experimentally or detect via observations. We cannot prove that our solution to the information paradox is unique. However, the consequences of quantum hair lead, without any speculative theoretical assumptions, to plausible unitary evaporation of black holes. The properties of quantum hair and the evaporation amplitude (6) can be deduced using only long wavelength properties of quantum gravity – they do not rely on assumptions about Planck scale physics or a specific short distance completion. Therefore, Occam’s razor favors quantum hair.

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