fsh

37 ms·

541.
by fsh 4y ago
The computational complexity of brute-force simulating many-body quantum systems scales exponentially in the number of particles. There is no supercomputer on earth that can simulate a realistic solid.
542.
by fsh 4y ago
Photorealistic renders for catalogs and architectural visualization can still take many hours on the best GPUs available (if the scene even fits into VRAM). Even a slight performance improvement can be worth a lot of money for companies doi
543.
by fsh 4y ago
L5 has a 10 times higher modulation ("chipping") rate than L1/2 which does lead to a narrower correlation peak width. However, it doesn't solve the multipath problem near tall buildings.
544.
by fsh 4y ago
That puts a lot of trust into the government correctly pricing in externalities. Otherwise, coal would steamroll everything since it is very cheap and abundant.
545.
by fsh 4y ago
Dual-band GPS allows detecting (and correcting for) multipath interference, i.e. signals bouncing off building and being received multiple times. This should improve accuracy in cities a fair bit.
546.
by fsh 4y ago
This is a wildly optimistic estimate. Even if we had an error corrected quantum computer that could evaluate an AES key (complete science fiction for the forseeable future), running Grover's algorithm would take millenia assuming extre
547.
by fsh 4y ago
This is incorrect. Quantum key distribution ("quantum cryptography" is a misnomer) is vulnerable to man-in-the-middle attacks. Security relies on having a pre-shared key which makes it essentially useless in practice (just use AES
548.
by fsh 4y ago
Is this some sophisticated parody, or are the authors serious about this complete nonsense?
549.
by fsh 4y ago
Telecom signal modulators are almost exclusively based on the Kerr effect or acousto-optics. Both effects have been known for at least 100 years and have nothing to do with nonlinear optics. The development of modern modulators was always d
550.
by fsh 4y ago
The first experimental demonstration was 18 years ago: https://www.nature.com/articles/nature03074 The problem is that none of this scales beyond toy systems with a hand full of qubits. As soon as you try making it big
551.
by fsh 4y ago
No, current quantum computers cannot do any practical computations. The gate errors are astronomical compared to even the earliest digital computers. Any algorithm with more than a few gates will produce just noise.
552.
by fsh 4y ago
I am not aware of a single telecom application that uses any of these technologies. Could you give some examples?
553.
by fsh 4y ago
A0 has an area of 1 m² and the long edge is sqrt(2) of the short one. This fixes the edge lengths to 841 mm x 1189 mm (rounded to the nearest mm). A4 is obtained by halving A0 four times.
554.
by fsh 4y ago
I have the impression that the problem of hydrogen leakage from vehicles is vastly exaggerated. A study on two commercial hydrogen cars found leakage rates of 2-6 mL/min (Table 4 in [1]). At this rate, it would take over 15 years for t
555.
by fsh 4y ago
The Iridium orbit heights are not much higher (781 km vs. 550 km). You can always trade bandwidth for increased sensitivity. The most extreme example is GPS. Your phone can receive it from 20000 km away with a tiny antenna, but the data rat
556.
by fsh 4y ago
This matches my experience. With a Gigabit Ethernet connection, I find it very difficult to distinguish a desktop streamed via Parsec from a local one. RDP is noticeably laggy in comparison. I would even say that Parsec over a good internet
557.
by fsh 4y ago
This is not how quantum mechanics works. One standard textbook example is to calculate the dynamics of a two-level atom that is perturbed by an oscillating (classical) electric field. The result is that there is a certain probability per un
558.
by fsh 4y ago
The double-slit experiment is no proof for the existence of single photons. It can be fully explained (at any light intensity) by assuming a classical electric field. The "clicks" of a "single-photon detector", such as a
559.
by fsh 4y ago
The quantum nature of light is extremely difficult to observe. Almost all laboratory experiments can be explained using Maxwell's equations and the quantization of the electric charge (this explains why photodetectors "click"
560.
by fsh 4y ago
Antennas do not emit or absorb electrons at all. Radio waves propagate at most at the speed of light.
561.
by fsh 4y ago
Tesla may have been a capable engineer in his early years (before turning into a crackpot and/or fraud). However, his understanding of modern physics appears to have been extremely poor. He certainly has not contributed anything signif
562.
by fsh 4y ago
The laser at NIF has a 0.5% efficiency [1]. Some lasers are highly efficient (for example diode lasers). High-energy pulsed lasers are usually not. [1] https://physics.aps.org/articles/v14/168
563.
by fsh 4y ago
All climbing ropes from reputable manufacturers are independently certified according to the European Norm EN 892. For example, here are the documents for all Black Diamond products: https://www.blackdiamondequipment.com/en_
564.
by fsh 4y ago
This is not a "bug" or an "issue", it is a matter of taste. Some users prefer search, others prefer a simpler "jump to file" function. The maintainers have decided to implement the former. Arrogant comments lik
565.
by fsh 4y ago
You are citing historical numbers for primary energy (mostly transportation and heating), not for electricity. ElectricityMaps has some live data for electricity generation: https://app.electricitymaps.com
566.
by fsh 4y ago
There is currently almost no gas used for electricity generation in Europe (much too expensive). Even under normal conditions, heating and industry consume an order of magnitude more gas than electricity generation.
567.
by fsh 4y ago
Auto-muting new users is not the issue (every reasonable video chat software does this). The problem is that in Zoom you have to "join audio" before hearing anything. I guess they do this since you could in principle also join t
568.
by fsh 4y ago
Protect them from what? Being able to listen to the call?
569.
by fsh 4y ago
The quality of the written documentation is also abysmal compared to HP times. One often has to guess how to correctly use gear that costs tens or hundreds of thousands of dollars.
570.
by fsh 4y ago
No, coal ash is not particularly radioactive. The amount of radiation released by burning coal is completely insignificant compared to the toxicity of the ash.

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