The truth remains that if you use "they" as singular you sound like a moron.
"Someone" has indefinite number and is not singular. Implicitly plural antecedents ("anyone", "everyone", "each ...") are not singular either.
672 karma · joined July 4, 2021
"Someone" has indefinite number and is not singular. Implicitly plural antecedents ("anyone", "everyone", "each ...") are not singular either.
The TPV is distinct from a solar cell because the TPV is meant to reflect energy back to the source. A solar cell also reflects some energy back to the sun, but that energy is effectively lost. In the TPV case, the reflected power helps keeping the source hot, thus effectively recycling photons in a feedback loop involving the source and the TPV.
Some of the energy incident to the TPV is transformed into electricity, some is reflected, and some is dissipated as heat in the TPV. The 40% efficiency is measured as (electricity+reflected)/incident. Thus, it is not true that the TPV converts 40% of its input into electricity. Instead, the TPV converts some fraction, reflects (40%-fraction) to be recycled later, and dissipates 60% into heat. Using the TPV as a solar cell would reduce the efficiency because the reflected energy is wasted. Part of the magic of the TPV is to design a really good mirror that reflects energy back to the source, which is not a concern for solar cells.
The current design operates best for a blackbody source around 2000K and there is probably no point in using it at 5600K.
Cool stuff.
(Presumably this is also true at sunrise, so the day is longer than it "should" be from purely geometric considerations.)
As a sibling poster commented, the blackbody spectrum was also inexplicable from a classical point of view (see https://www.feynmanlectures.caltech.edu/I_41.html Section 41-2), but I think that the specific-heat problem was known before the blackbody problem.
If the bot replaced "man" with "comrade" it would be accused of being Russian propaganda.
Here is what I think is a more modern understanding of the situation. It is true even in classical physics that a circularly polarized electromagnetic field carries angular momentum, and that E = L*omega, where E is the energy, L is the angular momentum, and omega=2*pi*f is the angular frequency of the EM field. See Feynman I-33 last paragraph, https://www.feynmanlectures.caltech.edu/I_33.html
Now, the experimental fact is that L is quantized in multiples of hbar=h/(2*pi). Thus you can derive Planck's results from the assumption that angular momentum is quantized. So the photon is really a quantum of angular momentum, which happens to have a non-quantized energy. But Planck's didn't know that, and worked with quanta of energy proportional to the frequency. (It's not like Planck was wrong. His theory was a necessary step towards the discovery of the deeper result that angular momentum is quantized.) Planck's constant of proportionality has the units of "action", which is the same units as angular momentum but "means" something different. The author starts with energy=action/time and attempts to reverse engineer the energy into quanta of energy, which as far as anybody knows do not exist, instead of starting with energy=angular_momentum*angular_frequency, where the angular momentum is truly quantized.
The author's theory falls apart when you realize that angular momentum in general is really quantized in units of hbar/2 (not for photons but for electrons), in which case her theory of energy being quantized in terms of a full oscillation of light becomes untenable, since you would have to quantize in terms of half an oscillation, at which point why 1/2 and not 1/3 or 1/4? Whereas there are legitimate geometric reasons why an object rotated by 360 degrees would change sign but yield the same physics. See https://www.feynmanlectures.caltech.edu/III_06.html
Up to a month ago, Russia could have shipped gas to Germany in exchange for "Euros", which means: Russia ships gas, and at the same time a number in a computer in Frankfurt goes up, reflecting the fact that Russia owns more Euros. Then Russia could go to a car dealer in Stuttgart and buy a Porsche 911 by spending Euros. Russia gets the Porsche and the number in the computer in Frankfurt goes down.
Now Germany is saying: the number in the computer is frozen. Russia cannot spend "Euros" to buy a Porsche. So Russia, understandably, says: These "Euros" are useless to me.
In this setup, no trade can happen anymore. The Euro is effectively worthless and the ECB has defaulted. As a compromise before things get worse, Russia is proposing an intermediate solution. First Germany sends the Porsche to Russia. To keep track of the transaction, a number in a computer in Moscow (a "Ruble") goes up. Later, Russia sends gas to Germany and the number in Moscow goes down to settle the balance. In order for this to work, the Porsche dealer or some intermediary must accept Rubles in exchange for the 911, and Germany must trust Russia not to freeze Germany's rubles (in which case Russia gets the Porsche for nothing and Germany is pissed).
How is this different from the '80s? First, many things in the 80's were done in physical bank notes, to which the "freezing" does not apply. However, the large amounts of gas trade make the exchange of physical bank notes impractical. Second, banks in the '80s would not have dared to freeze the money of their customers. Such breakage in the banking system is a new thing whose consequences remain to be seen.
[1] https://www.financialresearch.gov/working-papers/files/OFRwp...
[2] https://www.newyorkfed.org/medialibrary/media/research/staff...
It is hard to define exactly what a "Eurodollar" is, but for now assume that a Eurodollar is a bank deposit in a jurisdiction not subject to the Fed's authority. ("Eurodollar" has nothing to do with Euro the currency. People are surprised that "dollars" exist outside the authority of the Fed.)
A Eurodollar future is a contract to borrow a "Eurodollar" for typically 3 months some time in the future. The price of the future is quoted as (100 - interest rate). For example, the Sep 2023 contract (called GEU3) is currently priced at 97.225, meaning that people are agreeing to lend money for 3 months in Sep 2023 at a 2.775% interest rate. Now to my point: the Eurodollar futures curve is currently inverted starting in Sep 2023. For example, the price of the GEU4 future (Sep 2024) is 97.50, implying a 2.50% interest rate, or a rate cut in GP's parlance relatively to Sep 2023.
Why would you pay attention to Eurodollar futures? For one thing, the notional value of all futures is about $12T. (This market used to be larger than the Treasury bond market until Congress fixed the problem.) Like all markets, it may be right or wrong, but if you strongly believe that rates will not be cut between 2023 and 2024, there is a ton of money to be made in that market. The curve started getting nervous, with small inversions of 1-4 basis points, in December 2021, and the inversion has grown larger since. The inversion peak-to-through was ~30bp yesterday and is ~40bp after the Fed's announcement today.
The Bank of England published a summary of how modern banks work. See https://www.bankofengland.co.uk/quarterly-bulletin/2014/q1/m...
> It can't be just a number on a computer in a bank, right?
It can and it is, see the BOE paper.
> So I guess USD needs to be recognized by the US somehow?
This is a complicated question that will start a flamewar, but basically, any bank in the world can create dollars out of thin air given adequate collateral. Read about "Eurodollars".
The weird thing is not that there is a relationship between a function and its Fourier transform. That's pretty "elementary" math, as you observe. The weird thing is that physically meaningful quantities such as position and momentum should be related via Fourier transform in the first place. No amount of math can prove this fact---you need experiments.
By the way, in Heisenberg-type lower bounds, you allow both the function and its Fourier transform to be nonzero everywhere, yielding the result that the Gaussian distribution minimizes the product of the variances. But you can also ask a different question: assuming that I want the function to be band-limited, i.e., I want the Fourier transform to be strictly 0 outside an interval [-B, B], which function minimizes the dispersion in the time domain? This question yields the beautiful theory of the "prolate spheroidal functions", which are far from elementary. This kind of question is useful e.g. in signal processing: if you are allowed to look at N samples of an audio signal, what is the best low-pass filter that you can design?
To a first approximation, a libertarian would ignore all government statistics and instead look at markets. He sees the massive 10bp inversion in the eurodollar spot curve two years out, concludes that there is no (monetary) inflation, and positions himself for (monetary) deflation. He would agree with you that the CPI inflation has all the causes that you mention, perhaps throwing in lockdowns, vaccine mandates, and general government incompetence for good measure.
First, TFA states as much: "repo program that provided nearly $20 TRILLION in cumulative loans to Wall Street".
Second, the Sep 2019 repo crisis is well-known, it lasted multiple weeks, and it was big enough that the Fed wrote a postmortem about it: https://www.federalreserve.gov/econres/notes/feds-notes/what... You can read the details, but the Fed offered very short-term loans in the range of tens of billions, rolled over for an unusually long time.
For example, assume that I lend you $1000 for one day. The following day you pay me back $1000 plus interest, and I lend you $1000 for another day. We keep going for 1000 days, rolling over the debt. TFA would say I have lent you $1M. In reality, I have lent you $1000 for three years or so.
The statement that protons are indistinguishable is not strictly correct either, because protons have a spin. Protons with the same spin are indistinguishable, but you can tell apart protons with different spin. The spin of protons can only assume two values, so effectively there are two classes of protons, indistinguishable within the class.
In your specific case, it is clearly false that the probability of having one particle in one place is 200%. However, my statement still holds for expectations, and you end up with an expected two particles in one place. In the indistinguishable case, you must compute expectations based on amplitudes, not probabilities.
Before I say anything, if you have never heard of amplitudes before, you should read the Feynman lectures on physics vol. III, which you can find here: https://www.feynmanlectures.caltech.edu/III_toc.html Specifically read chapter 1 and chapter 3. The specific situation about distinguishable/indistinguishable particles is described in section 3-4.
Your question is kind of phrased backwards. Probabilities and amplitudes are human inventions to describe Nature's behavior, so by themselves they don't imply anything about Nature. The implication is the other way around: Nature has decided that some particle pairs are indistinguishable (proton vs. proton) and some are distinguishable (proton vs. neutron). Different rules apply to the two cases.
This indistinguishability is a pure quantum phenomenon. In a classical world, all objects are distinguishable---you can in principle label all protons and know which is which. But Nature does not work like that, and there exists this peculiar notion that you cannot tell two protons apart not even in principle. There is no deeper explanation of this phenomenon AFAIK---it is what it is.
You can tell experimentally whether two particles are or are not distinguishable by running the experiment as in Feynman 3-4. If you observe a distribution consistent with the add-amplitude rule, then the particles are indistinguishable. Any attempt to distinguish them leads to the contradictions explained in Chapter 1.
There is an even more peculiar phenomenon. Despite being indistinguishable, swapping two indistinguishable particles is not a no-op because it changes the amplitudes. You must still add amplitudes, but the amplitudes are different, yet different in such a subtle way that you still cannot tell the particles apart. Feynman 3-4 tells you how the amplitudes change during the swap, with a deeper explanation in chapter 4.
In quantum mechanics, probabilities are given by the square of the absolute value of more fundamental quantities called amplitudes. When something happens in two ways that can be distinguished, you must add the probabilities. When something happens in two indistinguishable ways, you must add the amplitudes, which yields a different probability after squaring. For example, .3^2+.4^2 != (.3+.4)^2. Thus, you can verify experimentally whether particles are or are not distinguishable.
Not that explicitly, of course, but let's go to https://diversity.berkeley.edu/rwle-books and click on "Anti-racism resources". We get to a google doc with a bunch of links, mostly broken or paywalled (so don't blame me for cherry picking).
Let's look at the first "Articles to read" https://www.theatlantic.com/ideas/archive/2020/05/americas-r... From that document I learn that there is a "racial contract" in America "rendered in invisible ink", which everybody tacitly agrees with (or at least all whites).
"The Declaration of Independence states that all men are created equal; the racial contract limits this to white men with property. The law says murder is illegal; the racial contract says it’s fine for white people to chase and murder black people if they have decided that those black people scare them. “The terms of the Racial Contract,” Mills wrote, “mean that nonwhite subpersonhood is enshrined simultaneously with white personhood.”"
But don't worry, "the racial contract is not partisan". Still, we can always blame Trump: "“We can’t keep our country closed down for years,” Trump said Wednesday. But that was no one’s plan. The plan was to buy time to take the necessary steps to open the country safely. But the Trump administration did not do that, because it did not consider the lives of the people dying worth the effort or money required to save them." (The people dying are understood to be nonwhite from the context.) You can read the rest of this delusional tripe.
Let's move to another article https://thebolditalic.com/where-do-i-donate-why-is-the-upris... America is full of white supremacists: "There is also evidence that much of the destruction has actually been instigated by white supremacists. This is not new. White Americans have a long, storied history of violence and destruction in this country." The rest of the article is actually somewhat reasonable, except for the occasional incendiary statement: "That white people, for all of our heartbreak and solidarity in public, often still operate in this way under even the smallest private pressure, so calculated and with such total disregard for Black lives."
Look, I get it. There is a history of horrible things, in the USA and really everywhere in the world. It's good that activists are drawing attention to the problems of historically oppressed groups. And for sure I'll defend their right to say whatever they want. I like to think I have even helped a little bit to make the situation better. I can live with the rhetoric, and in fact I would love to be in a world where people speak more directly, because it is easier to reach agreement if people spit out all their concerns quickly. But this kind of rhetoric is divisive and the fact that DEI office promotes it does not help the problem that they (and me and you) are trying to fix. What impression does the applicant get after being asked to write a diversity statement and going to the diversity website?
Then people take this stuff literally and you get the "pearl" that I linked. I easily admit that the example is extreme, but not as extreme and as uncommon as you may think. I'll leave it at that.
Good luck. I'll stop replying since this thread is way past its expiration date.