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nhaliday : quantum-info   63

If Quantum Computers are not Possible Why are Classical Computers Possible? | Combinatorics and more
As most of my readers know, I regard quantum computing as unrealistic. You can read more about it in my Notices AMS paper and its extended version (see also this post) and in the discussion of Puzzle 4 from my recent puzzles paper (see also this post). The amazing progress and huge investment in quantum computing (that I presented and update  routinely in this post) will put my analysis to test in the next few years.
tcstariat  mathtariat  org:bleg  nibble  tcs  cs  computation  quantum  volo-avolo  no-go  contrarianism  frontier  links  quantum-info  analogy  comparison  synthesis  hi-order-bits  speedometer  questions  signal-noise 
november 2017 by nhaliday
Quantum Supremacy: Office of Science and Technology Policy QIS Forum, Eisenhower Executive Office Building, White House Complex, Washington DC, October 18, 2016. Another version at UTCS Faculty Lunch, October 26, 2016. Another version at UT Austin Physics Colloquium, Austin, TX, November 9, 2016.

Complexity-Theoretic Foundations of Quantum Supremacy Experiments: Quantum Algorithms Workshop, Aspen Center for Physics, Aspen, CO, March 25, 2016

When Exactly Do Quantum Computers Provide A Speedup?: Yale Quantum Institute Seminar, Yale University, New Haven, CT, October 10, 2014. Another version at UT Austin Physics Colloquium, Austin, TX, November 19, 2014; Applied and Interdisciplinary Mathematics Seminar, Northeastern University, Boston, MA, November 25, 2014; Hebrew University Physics Colloquium, Jerusalem, Israel, January 5, 2015; Computer Science Colloquium, Technion, Haifa, Israel, January 8, 2015; Stanford University Physics Colloquium, January 27, 2015
tcstariat  aaronson  tcs  complexity  quantum  quantum-info  talks  list  slides  accretion  algorithms  applications  physics  nibble  frontier  computation  volo-avolo  speedometer  questions 
may 2017 by nhaliday
Dvoretzky's theorem - Wikipedia
In mathematics, Dvoretzky's theorem is an important structural theorem about normed vector spaces proved by Aryeh Dvoretzky in the early 1960s, answering a question of Alexander Grothendieck. In essence, it says that every sufficiently high-dimensional normed vector space will have low-dimensional subspaces that are approximately Euclidean. Equivalently, every high-dimensional bounded symmetric convex set has low-dimensional sections that are approximately ellipsoids.
math  math.FA  inner-product  levers  characterization  geometry  math.MG  concentration-of-measure  multi  q-n-a  overflow  intuition  examples  proofs  dimensionality  gowers  mathtariat  tcstariat  quantum  quantum-info  norms  nibble  high-dimension  wiki  reference  curvature  convexity-curvature  tcs 
- quantum supremacy [Scott Aaronson]
- gene drive
- gene editing/CRISPR
- carcinogen may be entropy
- differentiable programming
- quantitative biology
- antisocial punishment of pro-social cooperators
- "strongest prejudice" (politics) [Haidt]
- Europeans' origins [Cochran]
- "Anthropic Capitalism And The New Gimmick Economy" [Eric Weinstein]
There's an underdiscussed contradiction between the idea that our society would make almost all knowledge available freely and instantaneously to almost everyone and that almost everyone would find gainful employment as knowledge workers. Value is in scarcity not abundance.
You’d need to turn reputational-based systems into an income stream
technology  discussion  trends  gavisti  west-hunter  aaronson  haidt  list  expert  science  biotech  geoengineering  top-n  org:edge  frontier  multi  CRISPR  2016  big-picture  links  the-world-is-just-atoms  quantum  quantum-info  computation  metameta  🔬  scitariat  q-n-a  zeitgeist  speedometer  cancer  random  epidemiology  mutation  GT-101  cooperate-defect  cultural-dynamics  anthropology  expert-experience  tcs  volo-avolo  questions  thiel  capitalism  labor  supply-demand  internet  tech  economics  broad-econ  prediction  automation  realness  gnosis-logos  iteration-recursion  similarity  uniqueness  homo-hetero  education  duplication  creative  software  programming  degrees-of-freedom  futurism  order-disorder  flux-stasis  public-goodish  markets  market-failure  piracy  property-rights  free-riding  twitter  social  backup  ratty  unaffiliated  gnon  contradiction  career  planning  hmm  idk  knowledge  higher-ed  pro-rata  sociality  reinforcement  tribalism  us-them  politics  coalitions  prejudice  altruism  human-capital  engineering  unintended-consequences 
november 2016 by nhaliday
PHYS771 Lecture 9: Quantum
There are two ways to teach quantum mechanics. The first way -- which for most physicists today is still the only way -- follows the historical order in which the ideas were discovered. So, you start with classical mechanics and electrodynamics, solving lots of grueling differential equations at every step. Then you learn about the "blackbody paradox" and various strange experimental results, and the great crisis these things posed for physics. Next you learn a complicated patchwork of ideas that physicists invented between 1900 and 1926 to try to make the crisis go away. Then, if you're lucky, after years of study you finally get around to the central conceptual point: that nature is described not by probabilities (which are always nonnegative), but by numbers called amplitudes that can be positive, negative, or even complex.

The second way to teach quantum mechanics leaves a blow-by-blow account of its discovery to the historians, and instead starts directly from the conceptual core -- namely, a certain generalization of probability theory to allow minus signs. Once you know what the theory is actually about, you can then sprinkle in physics to taste, and calculate the spectrum of whatever atom you want. This second approach is the one I'll be following here.
exposition  teaching  physics  quantum  tcs  rhetoric  aaronson  tcstariat  lecture-notes  positivity  nibble  thinking  hi-order-bits  big-picture  quantum-info  signum 
may 2016 by nhaliday

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