Recent content by akhmeteli

M. O. Scully, M. S. Zubairy, Quantum Optics, Cambridge University Press, 1997 "as we shall see in later chapters of this book, there are many processes associated with the radiation-matter interaction which can be well explained by a semiclassical theory in which the field is treated classically...

Thank you for the information. By the way, what you describe seems similar to US patent 10625842 by Nathan Rapport.

Maybe your approach is better than mine, maybe it's worse, who knows. Are any details publicly available? I guess buckling is critical to your approach too.

And I am trying to do that, but it takes (a lot of) time. Making a vacuum balloon is hard: the idea is 350+ years old, but it has not been realized yet. As for our design, one of the challenges is making thin boron carbide plates (say, 0.1-0.2 mm thick). I cannot disclose what has been done in...

I don't know, maybe I completely misunderstand what you have in mind, but this is how it looks to me at the moment. Your design is supposed to withstand 88% of atmospheric pressure at sea level and also to be buoyant at high altitude, where air density is, say, one tenth of that at sea level...

So you seem to consider water vapor just as a means to prevent failure of the vacuum balloon on its way from the Earth's surface to its (high) design altitude. However, condensation strongly limits the water vapor pressure. If I am not mistaken, unless we have some exotic conditions, saturated...

Still, this is pain in the neck. It is one of the problems with helium ballons, besides helium being pretty expensive, nonrenewable, penetrating through pretty much any envelope. So I believe there can be at least some niche applications for low-altitude vacuum balloons.

Technically, yes, but there is such thing as Torricellian vacuum. There can be water vapor and nothing else in a container. Again, there can be water vapor and nothing else in a container. But I'd say you went off on a tangent when you started to talk about humidity. Condensation makes water...

At least the second statement is just your opinion. I used "exotic" for versions towed by vehicles, which require vehicles, roads, and what not. Let us consider a numerical example. Let us assume that the vacuum balloon has the radius of R=2.5 m, the air density is \rho=1.29 kg/m3. The maximum...

There is a difference between "helium is the winner of the race" and "low-altitude vacuum balloons do not have applications" That makes them an exotic solution even in the best-case scenario. I agree, but this is true both for low- and high-altitude vacuum balloons (and for helium balloons)...

Fixed towers of this height are (very?) expensive, they require some land to own or rent, they require lighting for aircraft safety, which creates serious maintenance problems. As for helium balloons, they have their own set of issues (don't get me started:-) ). Furthermore, helium balloons are...

At high altitudes, there cannot be "hot atmosphere" (unless one considers altitudes unreasonable for balloons). As for sea level, let us compare temperatures of 0 deg C and 50 deg C. The pressure of saturated vapor pressure at 50C is about 12% of the atmospheric pressure, but the air density...

But vacuum balloons can have some applications at sea level as well, so I don't understand why designing vacuum balloons for sea level would be a "big mistake". Technically, yes, but, for example, at the altitude of 150 m, the air density is just 1.8% less than that at sea level (and the...

I respectfully disagree. If the pressure difference between exterior and interior of the vacuum balloon is small, the shell needs to be very light to provide buoyancy, so it would be more difficult to prevent the balloon failure, in spite of the lesser pressure difference. According to our...

The abstract of my new article (Eur. Phys. J. C 84, 488 (2024)): The Dirac equation is one of the most fundamental equations of modern physics. It is a spinor equation, but some tensor equivalents of the equation were proposed previously. Those equivalents were either nonlinear or involved...