4 ms·

Wrote an article on the EmDrive some years back and have a little more insight on it than the average bear. Good to see the Dresden group is still plunking awa

Wrote an article on the EmDrive some years back and have a little more insight on it than the average bear. Good to see the Dresden group is still plunking away after all these years. Other than Eagleworks and a group in China, they were early leaders on verifying the concept. The law of conservation of momentum was created before quantum mechanics was discovered. Let's assume there's a base medium in which all energy (that is, mass) is embedded. Furthermore, let's assume there's a way to interface with this medium. The EmDrive works if one allows mass (that is, energy) to be transferred into this base medium. Momentum is conserved because the mass/energy is transferred to the all-encompassing medium. This medium is the same medium which enables quantum entanglement. In theory, the quantum vacuum and surrounding phenomena provides that medium. Frankly, I feel the classical interpretation of CoM is insufficient to explain the workings of the EmDrive. The article uses the phrase "a physics violation," but a more accurate statement is "a high-school level physics violation." How big of a deal is the EmDrive? It's an EM-wave-to-thrust device. Take a moment and consider the significance of such a device. Satellites could remain in space effectively forever, because solar panels continuously source the "propellant". Build one strong enough to counter Earth's gravity, and you get the hovercraft. As long as you have access to electricity, you can generate thrust. The article also mentions Salvatore Pais and his patents. His story took off after one particular Hacker News post and a comment on that post. You can read the full comment at the link below, but here's the most important points: "Whether or not the named inventor was a crank, and whether or not the invention was equally frivolous, this was a patent prosecuted by a Navy attorney, vouched for by the Navy CTO, and pushed through under atypical circumstances, in a public forum. What's even more intriguing is that, if the Navy wanted, it could obtain the patent under a secrecy order that would keep it from the public's eyes until it was declassified. Knowing all this, now ask yourself why this impossible sounding patent issued in a public forum with high-level brass support under tax payer dollars." https://news.ycombinator.com/item?id=19763445 https://news.ycombinator.com/item?id=19763445 My gut tells me the EmDrive works. Time will tell, of course.

Strilanc 6y ago
> if one allows mass (that is, energy) to be transferred into this base medium. Momentum is conserved because the mass/energy is transferred to the all-encompassing medium. This medium is the same medium which enables quantum entanglement. What are you talking about? Entanglement is not mediated by a medium. If it was, it would have speed of light limitations. This is like saying there's an unknown type of matter that enables statistical correlations to exist. It's mixing together incompatible concepts. Correlations just don't behave that way. Neither does entanglement.
- waterheater 6y ago
  >Entanglement is not mediated by a medium. If it was, it would have speed of light limitations. This medium is that in which all energy is embedded. Two particles becoming entangled does mean they're highly correlated with each other. But what enables this correlation? I don't see this question as answered, because wave function collapse is actively disputed. While my view of quantum entanglement is limited, I don't fully understand how entangled particles can be strongly correlated but can't transmit information FTL. Is it correct to say that two separate entangled particles are now one-and-the-same? I suppose you then get into a philosophical question of whether all parts of a system can ever observe the exact same thing at the exact same time. If this statement is false, then information must be transmitted, no? >unknown type of matter that enables statistical correlations to exist Matter and energy are one and the same. Why can't other types of energy exist which we don't fully understand? For example, how does dark "matter" work? We only have incomplete theories thus far, and I know of no paper that discusses physical manipulation of dark matter. The ether as a concept existed because people didn't understand the vacuum of space. But perhaps the zero-point field is a more accurate rendition of what etherians were trying to communicate.
  - Strilanc 6y ago
    > Is it correct to say that two separate entangled particles are now one-and-the-same? It's not. If they were literally the same then swapping them should have no effect, and you shouldn't be able to distinguish whether you applied effects to one qubit or the other. But often this is not the case. For example, the state |00> + |01> - |10> + |11> is a maximally entangled state but applying the swap operation to it produces a different state. And if I give that state to you, and you secretly apply a bit flip to one of the qubits before giving it back to me, I can do measurements that determine which one you flipped over. There are some entangled states where the swap operation has no effect, but there are no states where all possible operations on both qubits become identical. They're never literally the same.
    - waterheater 6y ago
      So, the entangled particles remain independent but highly correlated, that one can be used to determine information about the other (and vice versa)? Am I correct in reading that the broader scientific community doesn't fully understand the mechanism which enables this correlation?
cwillu 6y ago
> The law of conservation of momentum was created before quantum mechanics was discovered. The law of conservation of momentum is a fundamental part of quantum field theory; without it, we don't have particle accelerators, nor any understanding of particle decay. I strongly suggest, well, everything on this site, but in particular, https://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/ https://profmattstrassler.com/articles-and-posts/particle-ph... and https://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/ https://profmattstrassler.com/articles-and-posts/particle-ph... . It's the best review of modern physics I've seen anywhere that is both accessible to a lay-but-interested reader, and aligns correctly with the actual math.

Strilanc 6y ago

> if one allows mass (that is, energy) to be transferred into this base medium. Momentum is conserved because the mass/energy is transferred to the all-encompassing medium. This medium is the same medium which enables quantum entanglement. What are you talking about? Entanglement is not mediated by a medium. If it was, it would have speed of light limitations. This is like saying there's an unknown type of matter that enables statistical correlations to exist. It's mixing together incompatible concepts. Correlations just don't behave that way. Neither does entanglement.

waterheater 6y ago
>Entanglement is not mediated by a medium. If it was, it would have speed of light limitations. This medium is that in which all energy is embedded. Two particles becoming entangled does mean they're highly correlated with each other. But what enables this correlation? I don't see this question as answered, because wave function collapse is actively disputed. While my view of quantum entanglement is limited, I don't fully understand how entangled particles can be strongly correlated but can't transmit information FTL. Is it correct to say that two separate entangled particles are now one-and-the-same? I suppose you then get into a philosophical question of whether all parts of a system can ever observe the exact same thing at the exact same time. If this statement is false, then information must be transmitted, no? >unknown type of matter that enables statistical correlations to exist Matter and energy are one and the same. Why can't other types of energy exist which we don't fully understand? For example, how does dark "matter" work? We only have incomplete theories thus far, and I know of no paper that discusses physical manipulation of dark matter. The ether as a concept existed because people didn't understand the vacuum of space. But perhaps the zero-point field is a more accurate rendition of what etherians were trying to communicate.
- Strilanc 6y ago
  > Is it correct to say that two separate entangled particles are now one-and-the-same? It's not. If they were literally the same then swapping them should have no effect, and you shouldn't be able to distinguish whether you applied effects to one qubit or the other. But often this is not the case. For example, the state |00> + |01> - |10> + |11> is a maximally entangled state but applying the swap operation to it produces a different state. And if I give that state to you, and you secretly apply a bit flip to one of the qubits before giving it back to me, I can do measurements that determine which one you flipped over. There are some entangled states where the swap operation has no effect, but there are no states where all possible operations on both qubits become identical. They're never literally the same.
  - waterheater 6y ago
    So, the entangled particles remain independent but highly correlated, that one can be used to determine information about the other (and vice versa)? Am I correct in reading that the broader scientific community doesn't fully understand the mechanism which enables this correlation?

cwillu 6y ago

> The law of conservation of momentum was created before quantum mechanics was discovered. The law of conservation of momentum is a fundamental part of quantum field theory; without it, we don't have particle accelerators, nor any understanding of particle decay. I strongly suggest, well, everything on this site, but in particular, https://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/ https://profmattstrassler.com/articles-and-posts/particle-ph... and https://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/ https://profmattstrassler.com/articles-and-posts/particle-ph... . It's the best review of modern physics I've seen anywhere that is both accessible to a lay-but-interested reader, and aligns correctly with the actual math.