Danijel Gorupec

Off-topic, but IMHO important: please note that the square of the light speed is not equal to the double of the light speed. It seems to me that you might mix these.

Thanks guys. After reading all your comments, I must conclude that the space-momentum entanglement is not what I was originally thinking it is. For some reasons (that are fundamental but unknown to me) there exists some uncertainty between entanglement particle trajectories – it seems that the angle between their paths cannot be guaranteed. I see no other explanation. Therefore, in my original post, Alice will have difficulties to influence Bob’s display. Greater the distance between displays, larger the difficulties. Obviously, now I have the new problem – understanding what exactly the space-momentum entanglement is.

Enthalpy, I think you might be correct – some fuzziness might happen at the B side and therefore Alice cannot influence Bob’s display if two displays are sufficiently distant. I also understand your point about ‘entangled particles not perfectly opposed due to emitter recoil’. But are you sure this is true, or you are just guessing? I thought that momentum-entangled particles are perfectly opposed. In addition, is this recoil behavior fundamentally unavoidable and always large enough? Anyone knows? I actually don't think the method makes difference. The setup is central-symetrical regarding to the particle source. If Alice knows through what slit the particle passed at her side, she also knows through what slit the entangled particle passed on Bob's side.... However, as Enthalpy said, this is questionable. Also, I can add, the particle source is hardly a point... Only I don't know if these reasons are fundamental or practical. BTW, I don't know about how in practice they obtain the 'which path' information in real double slit experiments. In most double slit experiment descriptions, nobody cares enough to explain the dirty part.

I dont' believe in FTL communication. But when I created this 'experiment' I was not able to find any reason why this would not be the FTL communcation. This puzzled me.... In my experiment the particle source is in the exact middle between two opposite displays. Therefore, I expect, both entangled particles will reach displays at the same time. If now I imagine these two displays separated by a light year, there should be enough time for Alice to construct/destruct the pattern at Bob's side. I am searching for a reason why this should not be possible. Maybe, as the distance between displays increases, it becomes fundamentaly harder and harder to somehow 'aim' particles at slits - or there is any other reason why the time needed to confirm the pattern would also increase. In your first paragraph, do you reference the actual Quantum Eraser experiment, or the similar experiment I am proposing in OP?

I would like to know more because I don't see it. Obvously there is something I don't understand. I only wish you are right . And I wish we are all victims of "Quantum Parading" [when physicist present world in a more bizare light than they should - just to earn themself higher chance to pick up a girl (or funds). You see, the world is all about probability ].

Hmm.... I feel that words like "one could tell" and "detecting" are somewhat overused. In the Quantum Eraser experiment one should say: "filters are placed in front of slits so that no single photon can travel through both slits at once, and therefore the interference pattern disappers". No need to use mistical words that involve consciousness. Anyway, the second part of my OP question was - is this the faster-than-light information propagation (Alice can send Morse code to Bob by destroying and establishing the interferrence pattern on Bob's display)? Can anyone comment? Thanks.

I think I understand. You tell me that entangelment does not need to contain all properties - only some properties can be in the entangled state... Does it mean that even non-identical particles (not even particle-antiparticle pairs) can have some properties entangled? I am a "Quantum Newbie". I read about the Quantum Eraser experiment. The setup is very much like the one I am talking about... I am not sure I understand the 'delayed' part. Does it mean that the "faster-than-light" action is not strange enough; that there is also "time order is not important" action?

A double slit experiment is performed. In the middle of the experiment table, there is a particle source. The source emits entangled particle pairs, one by one. The two particles in each pair are, of course, emitted in opposite directions. There are two identical double-slit experiment setups - the left one (A) and the right one (B). Each setup consists of one screen with two slits and one display screen. The fringe pattern is visible on both displays screens, A and B. Is this true? Or is there any reason why there would be no fringes in the case of entangled particles? If the experimenter at the side A (Alice) now makes a measurement effort to determine through which slot each particle actually traveled, the fringe pattern disappears. Because particles are entangled, fringes will disappear simultaneously on both, the A and the B side (even if the experimenter at the B side (Bob) made no similar measurements). Do I understand this correctly? Alice can make immediate effects on (possibly very distant) Bob’s display.

No warp drive... Still, I will pay my part if he rebuilds Seven-of-nine (Borg technology, I know, but maybe it can be done).

I was hoping that maybe water could be heated for about 20-30C, to reduce water consumption.... But you are right, hardly there are such units on the market - no demand... The glass-walled room is in the middle of a large hall and gets fresh air (non air conditioned) from there. During hottest days, some cooling would be very much needed.

My friend rents a room in a building. The room is in the middle of the building - no outside walls, no outside windows. No way to make a vent for a portable air condition unit (refrigeration type is needed). However there is watter supply and watter drain. Does anyone know if there are small air condition untis that are able to pump heat into the watter? I don't even know what term should I google.

Can you provide more details. I am interested in this technology... Does it mean that the electrode must be thinner than 0.1mm? Do you spend one electrode per one hole? What is the drilling speed? I suppose you can drill metals only? What parameters you can vary on your equipment? Finally, why is sparking only happening at the electrode tip - I suppose that hole walls are not very smooth? Thanks (no one else to ask).

Do you consider those symbiotic bacteria to be organisms? Long time ago I accepted the following rough "definition" of life: a 'mechanism' able to maintan its complexity in a less complex environment. Now I don't know what to think about those symbiotic bacteria .

If I understood the article correctly, the U-TDOA and GSM have approx. equal accuracy. Still, 50m error seems not good enough to isolate a room - 5m is needed. I suppose that: - if the error has no bias (low precision), then better results could be obtained by longer-time averaging. - if the error has bias (low accuracy), then, maybe, it is possible to search for large groups of still-standing mobile phones (large concentration of mobile phones on small area) near the target room location and conclude that this actually is the target room. (Note: not all service features need to be switched off, so 911 calls could remain)

How precise can a mobile phone operator locate a hand set position? What factors contribute to that precision? I was thinking if it is possible for a mobile phone operator to simply exclude a single building (or even large room inside a building) from the mobile-phone service? For example, would it be possible to arrange with mobile phone operators to exclude cinema halls or school classrooms from its service? I am aware that mobile phone operators would have no interest in doing so, but law can be adjusted so that they must comply (in some cases, at least)... Do you already know a mobile phone operator offering such posiblitiy?

Yes, it was not very smart not to write down these data when I had my chance (together with BIOS brand and version). Sorry. It seems that I will have to prepare several most likely solutions and apply the right one durring 'commissioning'.

I actually hope that once the power supply is powered on, the +5V will be generated and: - in case A) it will pull-up the power-on line - in case B) it will pull-down the power-on line by activating the transistor. Therefore, the power-on signal will not be active any more. But there might be some traps I don't see.

I have one "stupid" problem... I ordered an embedded fanless computer that doesn't turn on automatically when power is supplied. Instead it waits for someone to press the power-on switch. I found no BIOS option to solve this problem (there is no "power on after power faliure" or similar options in BIOS, or at least I couldn't find it). I only had a brief time to examine the computer (had to ship it to its final destination). I found that: - as I said, no BIOS option can help me - the ATX-like power supply is integrated on a single multi-layer high-density printed circuit board - the power-on switch leads are the only accessible places where I can solder wires. I can also access +5V, +12V and GND from a SATA connector - one power-on switch lead is at 3.3V, and the other is GND - a momentary short-connection of power-on switch leads will turn the computer on. A permanent short-connection will turn it off, unfortunately. - using a 1 kohm (or less) resistor between power-on switch will still turn the computer on (a perfect short-circuiting is not needed) I don't know how exactly the power-on button works. I suppose that there are two posbilities: A) it drives the power-on line to GND [look at drawing A) on the picture] B) it drives the power-on line to +3.3V [look at drawing B) on the picture] Does anybody know what option is more likely, A or B? (As I said, I don't have the computer any more to make the test, and I forgot to make this test when I had oportunity). I will atempt to solve the problem by making a small circuit around the power-on switch. Solutions for A) and B) are also pictured. Do you think this will work? Any better idea?

As far as I understand, maglev trans are not about energy saving (malevs offer other advantages: 'unlimited' speed, low noise, high ride quality). However, in theory maglev trains do not need to consume much more energy than wheeled electrical trains - just a small fraction more. In fact, if you make them confortable and fast enough to replace some other means of transport (cars, planes...) then, maybe, you can make some overall energy savings.

Disagree. In general, I think, hardest are commercial issues - the constant 'battle' with expenses (and your competition). You will find this in every engineering field.

Thanks for all your comments... I agree that using tilde in front of a number is mathematicaly the most correct way to represent a non-exact value. There are however practical disadvantages of this notation: - representing negative numbers seems awkward: ~-10.3 - at low-resolution montior, or small font, the tilde sign may look like the minus sign. - adding the tilde sign in front of a number affects rendering (typesetting) heavily as longer numbers affect alignment - the tilde sign in front of a number does not explain the reason of non-exactness. Therefore, in my software, I will probably opt to use the "tilde below the last digit" to represent non-exactness because of rounding. (I will print this tilde in a pale color to generate less distraction). One general note: math notation is not perfect (for example, Leibnitz's calculus notation). As a result, I am not too afraid to 'expand' the notation in a new direction. After all, mathematicians are bright people and should be able to learn few exceptions when using particular software. Of course I know the LaTeX.... As you said, the LaTeX is designed for publishig, while my software is designed to type personal notes rapidly. Some LaTeX commands are implemented, but it is not possible to implement the full set due to different software philosophy.

Whoooow! Now you got me thinking about three nice posibilities: - tilde sign over the last digit - tilde sign under the last digit - small plus/minus signs at the bottom right corner of the last digit First two propositions are very easy to implement and very intuitive to understand. The third proposition, on the other hand, gives additional info about the exact value (wheter it is smaller or greater). Most certainly I will implement one of these three propositions. If anybody else wants to vote, please do so (It is to be used in Math-o-mir software: http://gorupec.awardspace.com/mathomir.html )

Thanks for your introduction... From what you said, only the proposition to somehow enclose the last digit into the parentheses is useful for my purpose. The reason for rounding in this software is simplification, and therefore only a simple indication mathods of rounded numbers are meaningfull. In the mean time I had another idea... to put a very small + (plus) or - (minus) sign at the bottom right corner of a rounded number - indicating that the exact value is actually a bit greater or smaller. What do you think? If such indication is alreday used for an other important purpose, maybe it is not a good idea. Also it is the question of monitor resolution, how small +/- sign can I render.

I need to present rounded numbers in my software. For example, after calculating "sqrt(2)", the software could display the result as: "1.414" (it only shows the result to a 'reasonable' precision). How to mark this number as a round-off number? Is there a standard notation in mathematics? From the displayed value it should be immediately visible if the result is rounded or exact. For example, consider the following two cases: 1/8 = 0.125 (the exact value) sqrt(2) = 1.414 (rounded value) If there is no standard way to somehow mark numbers that are rounded, I was thinking to put a dash under (or over) the last digit. Or maybe printing out the last digit in a pale color. What do you think?

This seems logical for non-painted steel... However, if rust is sealed with paint, this effect shuld be much smaller (limited by paint permeability). But it seems that sealing rust with paint does not slow the rusting process.