Quantum Thoughts - fcrimins/fcrimins.github.io GitHub Wiki

Quantum Thoughts Summarized in Prose

On entropy:

  • Has every makeable movie been made? No. In what domain is every configuration (equally) possible? I can't think of any that aren't artificial. Uniform distributions just don't happen. So why would we expect physics, the universe, to be any different? Just because we can't see the order in a box of gas particles doesn't mean it's not there.

Dark matter == constructive interference

  • Caused by regular matter all moving in tandem with itself? Thus causing a moving "static" miniverse?
  • This doesn't happen nearer galaxy centers because there is stuff nearby moving in different trajectories.
  • There either needs to be more matter or more spacetime curvature, which would typically be due to matter. But if there is constructive interference then maybe that extra curvature can come from there instead.
  • https://www.reddit.com/r/pbsspacetime/comments/4ejgs6/could_dark_matter_be_the_constructive/
  • "Dark matter" should be called "Dark space-time curvature" b/c it's not clear what's causing the curvature--saying that it's "matter" is an assumption.

Quora: What is dark matter? (1/4/17)

Quora: How come the stars at the outer edge of the galaxy are rotating at the same speed as the stars towards the center? (1/4/17)

  • However, even though we have not yet had direct detection of dark matter particles, there is now a mountain of evidence pointing towards its existence; in other words, in this case, it's #1 (Maybe there's matter we can't see, e.g. Neptune), not #2 (Maybe our theory of gravity isn't quite right, e.g. Mercury).
  • FWC - so we've experienced both #1 and #2 right here in our solar system--with only 8/9 planets--huh? Given that, what are the chances that these concepts aren't enormously more complex than we might find by chance right here at home.

Grand Unification Dream Kept at Bay (1/2/17)

  • Physicists have failed to find disintegrating protons, throwing into limbo the beloved theory that the forces of nature were unified at the beginning of time.
  • Over the past four decades, physicists have proposed a variety of GUT models that describe possible initial symmetric arrangements of the particles. Finding out which model is correct would reveal not only the underlying mathematical structure of nature’s laws (and how they might square with the fourth force, gravity), but also what other particles might exist besides the known ones. This in turn could potentially solve other deep mysteries of physics, such as the universe’s matter-antimatter imbalance and the unexplained masses of neutrinos.

Quantum Gravity’s Time Problem

  • "many leading physicists now consider space-time and gravity to be “emergent” phenomena: Bendy, curvy space-time and the matter within it are a hologram that arises out of a network of entangled qubits"
  • "time doesn’t exist globally, but an effective notion of time emerges for the subsystem."

The Case Against Dark Matter (12/5/16)

  • "A proposed theory of gravity does away with dark matter, even as new astrophysical findings challenge the need for galaxies full of the invisible mystery particles."
  • "De Sitter space-times like ours stretch as you look far into the distance. For this to happen, space-time must be infused with a tiny amount of background energy — often called dark energy — which drives space-time apart from itself."
  • "disrupted by the presence of matter, which essentially removes dark energy from the region of space-time that it occupied. The dark energy then tries to move back into this space, exerting a kind of elastic response on the matter that is equivalent to a gravitational attraction." [FWC - this is similar to my idea that DM and DE are opposites of the same effect, one pushes on the other]

The universe is a partial function. (10/6/16)

Email: False vacua (p. 326) (2/6/16)

  • It is an optimization! A false vacua is a local minima in terms of energy

Email: Inertial and Gravity... (1/31/16)

  • ...are the same thing. The same force that makes acceleration take energy is the force that controls gravity. Inertia is just curved spacetime in the presence of matter. So it's like gravity wrt one's self

Email: When... (1/29/16)

  • ...in the history of the universe, has anything ever moved away from something else at a precisely accelerating pace? Never. Things move in spirals. Dust just doesn't move like that.

Email: Is dark energy (1/11/16)

  • Equal to time? Eg if the universe stopped expanding would time stop?

Will Quantum Mechanics Swallow Relativity? (1/3/16)

  • Great article on the tension between quantum mechanics and general relativity.
  • Plus some guys who have theories seemingly orthogonal to the prevailing consensuses. One of which has to do with the possibility that space may be discrete--quantums of space.

Email: The Multiverse episode of the Astrophysics Yale class for beginners podcast (10/29/15)

  • MoND - Modification of Newtonian Dynamics, gravity is different at large vs small distances. FWC - makes sense, yes, because space is stretched differently at both
  • FWC, or how about this, the gravity of a black hole is different bc no electrons, like a neutron star, bc electrons can only get so close together, electron degeneracy
  • Anthromorphic Principle - if you choose a bunch of physics constants randomly you don't have what it takes for life to exist. This suggests that random choices aren't consistent w each other. Take Euler's equation for example. You can't just choose any values for pi and e and i. I wonder if given the values of the constants the equation could be computed using prolog or something.

Email: Acceleration slows down clocks (10/26/15)

  • Because of the momentum of the vibrating/oscillating components, both of which take energy.
  • So do different trajectories with the same acceleration have different effects on clocks? Akin to constructive vs destructive interference?
  • Does a clock move slower in an accelerated path because there has to be something providing power to the vibration of the clock's crystal and that same "thing" is providing power to the accelerated path? I.e. there's only so much power to go around so the accelerated path sucks power from the clock. Is this "power" the dark energy? What makes quartz crystals oscillate? Is it dark energy? If so, is dark energy responsible for quantum oscillations also?
  • Is the gravity of cold stuff less than that of hot? Stuff moving near the speed of light has more gravity. Does Bose-Einstein condensate (BEC) have very little gravity? Do quantum fluctuations create gravity?

Email: the entropy of a state (p. 173) (10/23/15)

  • The entropy of a state shouldn't be defined as the precise state the system is at at a specific point in time. It should be defined by the probability distribution of all possible future states.
  • The further in the future you go, the less likely the specific-point-in-time entropy will be smaller, just like the stochastic volatility grows with the square of time while drift grows linearly.
  • Perhaps the past should be thought of the same way, as having been derived from a distribution of possible pasts.
  • This reminds me of light cones.
  • Email: Oct 8 (which is mentioned as God's birthday) in star talk episode with God (10/28/15)
    • Plus, perhaps entropy should be defined as the difference in the distribution of possible past entropies vs. that of possible future ones. Kinda like the derivative of an integral.
    • Or: make entropy the inverse of all the impossible microstates as opposed to the number of possible ones.
    • Maybe the Time Reversal Hypothesis is true not because the past is fixed and the future is uncertain, but because the past is uncertain in just as many ways.

Email: From Here to Eternity (Sean Carrol's book) quote (9/30 - 10/23)

  • "An unaccelerated trajectory yields the greatest possible time a clock could measure between two events." (p. 85)
  • So acceleration effectively slows down time. Either that, or time is linear and acceleration bends space. I.e. the path of the accelerated object while seemingly longer in typical units of distance (such as kilometers) is actually shorter in acceleration-adjusted units (such as accelometers?). So rather than acceleration slowing down time, perhaps it shrinks space. (Also note that an "unaccelerated trajectory" is effective deceleration w.r.t. the acceleration of the expansion of the universe.)
  • It makes sense that duration (i.e. change in time) is shorter when something accelerates off into space and comes back. If this occurs where one object does not accelerate and another goes off and comes back, both objects have traveled the same "distance" in spacetime. They both started at the same location (in space) and at the same time, and they both ended at the same location and time. One object traveled a longer distance though, so if spacetime "distance" is (reasonably) some monotonic function, f, of both space and time, say f(s, t) = sqrt(s^2 + t^2), then when s is larger for an accelerated object, t must be smaller.
  • This could also have something to do with why it's impossible to travel back in time. If time is a sort of (non-directional) distance metric then that would be the case; distances can't be negative. E.g. what if time actually does have multiple dimensions with a functional form similar to Euclidean distance: t = sqrt(t0^2+t1^2+t2^2)? The value of t can't ever be negative.
  • As an aside: Doesn't velocity slow down time also, as in the "speed" of light? Or maybe there's a 3rd derivative involved; something along the lines of: acceleration matters for low speeds while velocity matters for high speeds. A 3rd derivative would perhaps relate to the 3 dimensions of space and/or explain why the speed of light is a limit. In other words, does acceleration matter less (w.r.t. time) and velocity more as velocity increases?
  • Also, dark energy as the reason for the acceleration of the expansion of the universe seems improbable to me. It seems like a correction factor for something wrong with the underlying model, which otherwise (in the absence of dark energy) implies contraction due to gravity.
  • Perhaps time doesn't increase if not for the acceleration of the universe.
  • Relativity says that gravity bends space; it redefines what is accelerating and what is not; e.g. something in orbit is not accelerating; it changes how distances should be computed from typical units of distance (like kilometers) to gravity-adjusted units of distance (like accelometers?).
  • Wasn't there massive acceleration at the beginning of the universe, just after the Big Bang? If that's the case, then maybe that's why we observe it as having happened so quickly. I.e. acceleration = space / time where time is near 0. Or rather, if acceleration shrinks space, then perhaps that why we observe the Big Bang culminating from a single point. Black holes with their massive acceleration/gravity could also just be larger areas of typical space shrunk down.
  • The speed of light shrinks space down to 0. It's the inverse of space. That's why nothing can travel faster.
  • Time = Gravity (which also can't be negative)
  • The universe is exponential; nothing is linear. Anything with a limit (the Big Bang, the speed of light) is really the inverse of something else. Prediction: the acceleration of the universe is exponential.
  • Gravity is acceleration and acceleration shrinks space. So why is gravity acceleration? Maybe because electrons spin around atomic nuclei. This would suggest, however, that electrons in different orbits generate different gravity and thus have different mass.
  • Acceleration of the universe = dark energy = gravity = shrinking of space = speedup of time
  • Disc galaxies = dark matter = not enough matter = lots of non accelerating objects in orbit = slow down of time
  • "The energy of an object at rest is proportional to its mass." (p 80)
  • "'relativistic mass,' which increases when an object is in motion." (p 80)
  • Future times of the universe are much longer durations, 10^90, than past, 10^-30; i.e. time is exponential. The beginning of the universe only looks like it happened so fast from our perspective.
    • Dark matter = centrifical force
    • Dark energy = linear acceleration
    • Episode 26 Phil Plait - just after the big bang
    • Think more about the inverse relationship between temperature and pressure. The universe started out very hot, and now it's only a few degrees (2.7?) above absolute zero.
  • Page 110: "how spacetime avoids making a time machine--it crunches to zero volume before the closed timelike curves are created."
  • Can 2 bodies of mass travel past each other at 3/4 the speed of light, thus their relative speed is 1.5 c?
    • A: No, because of relativistic mass; they'd be pulled towards each other by gravity.
    • Is this a fundamental limit on the stretchiness of space?
  • In response to what I wrote earlier: "Or maybe there's a 3rd derivative involved; something along the lines of: acceleration matters for low speeds while velocity matters for high speeds."

Email: The ice cube in the glass of water (10/22/15)

  • Is not an example of the irreversibility of time because it's not a closed system. Something had to put the ice cube there. So even though the resulting state after melting is a cold glass of water, the resulting state of the rest of the system is different than it would be if it had just begun as a cold glass of water. * The fact that something is different means that time may be predictive in reverse.
  • Counterpoint: take 2 causes and swap them with their effects.
  • Counterpoint #2: dropping ice cube in water and waiting 5 minutes, vs waiting 5 minutes and then dropping the cube in. Rearrange the order of causes. Resulting state an hour later is the same? Perhaps not: is the state of your arm the same? Is the amount of information the same? You had the thought of dropping the ice cube in for a longer amount of time, didn't you?
  • Conservation of information, p. 167
  • Is space referential to the observer? Or is it time? Or both? Referentiality? Or relativity?
  • Multiple arrows of time, p. 171, bottom: These sentences show that time is self referential to the observer, the experiencer of the time.

Email: Perhaps the second law is backwards (10/21)

  • It's not that entropy increases with time, but rather that time increases with entropy. Acceleration, the second law, gravity, dark energy & matter, they all have time in the denominator. Perhaps they are all the same effect--i.e. movement through (dense) space over time.

Email: 4d spacetime = "Cartesian spacetime" (10/14 - 10/21)

  • Except there's good evidence a f ain't Cartesian, so why try so hard to hold on to that concept? Trying to make everything agree is doomed from the start.
  • Evidence that time is different [from space] is in the paragraph at the bottom of p. 123 [of Sean Carrol's book].
  • Rather than having 3 dims of space and one of time, one could imagine having 3 of space and one of velocity, and then time can be derived from that. Then you probably need acceleration though also, etc. I.e. a single dimension of time isn't enough to describe the state of spacetime.
  • p. 130, momentum = mass * velocity; and in relativity momentum goes to infinity as v approaches c (relativistic mass/velocity)
  • Acceleration can't happen without adding energy so perhaps its energy that affects (ie speeds up) time. E.g. what if you heat up a clock? Will that slow time down?
  • In physics, credit accrues not just to someone who makes an offhand suggestion, but... (p. 138)

Time = Gravity

Email: Another dimension (10/12/15)

  • If there were another dimension that we don't know about, that could explain why accelerated trajectories take less time. I.e., we aren't including all of the relevant dimensions in the spacetime equation.
  • Perhaps gravity/acceleration is that additional dimension. Just like in that MIT machine learning video on SVMs (towards the end) where he adds another dimension to make large margin classifier work in the presence of noisy data.
  • Perhaps "space density" is that other dimension, though this would clearly have to be dependent on gravity/acceleration.

Email: Does time travel through space? (10/10/15)

  • Like sound travels through air?
  • Lookup that aether experiment. (I.e. is space time's aether?)
  • You also can't have negative sound. (There are lots of things with limits, like the speed of light.)

Email: Discrete Time (10/8/15)

  • Is there any reason to think that time is continuous? Is anything continuous? Particles? Fields? Why would time be? Maybe because gravity is? I.e. because time is a distance metric.

Email: If the expansion of the universe is accelerating (10/8/15)

  • Then we, our galaxy, must be accelerating in some direction, but why can't we feel it?
  • A: Because it's not that objects are accelerating through space; it's that space between objects is growing/stretching at an accelerating rate.
  • Podcast: Ep. 279 Hubble Constant | Astronomy Cast (10/21/15)
    • It's not that distant galaxies are accelerating away from us; it's that the space between us and distant galaxies is expanding causing them to appear like they're accelerating away.
    • This is why we, and they, don't feel the acceleration?

Email: Gravity and universe expansion are related (9/29/15)

  • The hypothesis (prior to dark energy) was that gravity would slow it down. But what if cause and effect are wrong. What if universe expansion causes gravity. At the moment of the BB there was no gravity.

Email: On pg 81 (or on a piece of paper inserted) of Sean Carroll's book (9/29/15)

  • Draw 3 2d squares representing space at different points in time. And make a circle move across the space, changing position at each. This is a massive object moving through time.
  • Below this, draw another series of squares, but this time put the 3 locations of the circle all in the same square. This can't happen of course, but this is what it would look like to move through space while time stands still. This is outside the light cone.

Email: "Bumpiness and randomness"

  • Create smoothness. Things work better when they are disorganized. [just as with machine learning: randomization is the key (to optimization in high dimensions)] Perhaps this applies to quantum mechanics

Email: "Randomness doesn't come up in nature"

  • It only comes up in stuff like markets and sports where sentient beings are competing. Perhaps it does in nature tho, eg when species compete. The point is that perhaps quantum mechanics is some sort of competition also, and if we understood it better we could predict it better

Email: "Predictability of anything is a figment"

  • Quantum unpredictability is transitive with the unpredictability of fate

Email: "If stuff like..."

  • ...light and radio can travel through space, that must mean that consecutive chunks of space can pass the waves from chunk to the next, which means they must be nonempty. Perhaps particles that have twins are chunks of space that have been separated, ie noncontiguous space.
  • is space is discreet, just like quantum leaps, b/c this would also suggest the discrete chunks could be separated

Idea: the Big Bang as a finely tuned boundary condition

  • "If our universe began at the Big Bang, it is burdened with a finely tuned boundary condition for which we have no good explanation. But if the observed universe is part of a bigger ensemble--the multiverse--then we might be able to explain why a tiny part of that ensemble witnesses such a dramatic change in entropy from one end of time to the other."
  • But what if the beginning of time is like Absolute 0 temperature, which is another "finely tuned boundary condition?
  • An odd thing about this is that temperature is related to pressure, and so this might relate to my space pressure idea where matter is the absence of space, i.e. low space pressure, the source of gravitational fields (objects being attracted towards each other due to low space pressure).

Email: Time, gravity, and the curvature of space (7/10/15)

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