
20220817: What If Dark Energy is a New Quantum Field?
 00:36: ... intense over time rather than having a constant density expected of a vacuum energy. That would cause the universe to eventually tear itself apart on a ...
 05:18: ... fluctuations. For example, it’s actually very difficult to get the vacuum energy to be very close to zero but not quite equal to ...
 05:50: ... each other out. A perfectly symmetric canceling could get you down to a vacuum energy of zero, but it’s really really hard to cancel such a large number down ...
 10:55: ... fields, it could potentially cancel out their predicted extremely high vacuum energy in a natural way, so that dark energy becomes the tiny residual from ...


20220525: The Evolution of the Modern Milky Way Galaxy
 18:10: ... There would indeed be an additional effect due to the tiny vacuum energy inside the galaxy. However the effect is minuscule, ...


20220223: Are Cosmic Strings Cracks in the Universe?
 04:51: ... the same part of the Higgs minimum. A bubble of this lower vacuum energy was nucleated, and it expanded at the speed of light. ...
 07:33: ... the defect tighten as much as they can. The filament of high vacuum energy is squeezed it down to onetentrillionth the width of ...


20220210: The Nature of Space and Time AMA
 00:03: ... new space in a sense um in this that that new space has the same vacuum energy density the old one has the same kind of behavior of virtual particles ...


20201118: The Arrow of Time and How to Reverse It
 10:34: ... to be yes, at least to some degree. The Higgs field sits at a nonzero vacuum energy so could potentially decay to zero, or even to a lower nonzero state ...


20200608: Can Viruses Travel Between Planets?
 15:22: ... the Casimir effect is thought to be due to an alteration in the vacuum energy between a pair of conducting surfaces, which leads to those surfaces ...
 15:49: ... agrees with socalled lifshitz theory, which is based on this altered vacuum energy ...


20200203: Are there Infinite Versions of You?
 08:17: But universes with large vacuum energies will exponentially expand, until that vacuum energy decays to lower values in smaller regions within.


20191111: Does Life Need a Multiverse to Exist?
 09:29: ... problem is, when we try to calculate the strength of this vacuum energy from our theory we get an enormous number  10^60 to 10^120 larger than ...
 09:49: If fact, that’s true if the strength of vacuum energy were only a little larger than is observed.
 10:25: ... there are other theoretical ways to get the vacuum energy to take on different values in different regions of the universe  or in ...
 11:24: ... suggests that the values of the fundamental constants, including the vacuum energy, are set by the particular configuration of the extra coiled dimensions ...
 12:04: ... and in each bubble the constants of nature  and especially the vacuum energy  taking on different ...


20190819: What Happened Before the Big Bang?
 01:47: It had a nonzero vacuum energy.


20190806: What Caused the Big Bang?
 03:42: The speed of that exponential expansion depends on the strength of the vacuum energy density.
 04:32: So, the vacuum energy would need to drop from a very high value to basically zero.
 07:06: We would call this a false vacuum and it gives us exactly the constant vacuum energy density needed for inflation.
 07:13: There are other ways for a field to end up with a positive vacuum energy density and I'll come back to these.


20190320: Is Dark Energy Getting Stronger?
 02:13: Mathematically we represent a constant vacuum energy with Einstein’s cosmological constant – or Lambda.


20180920: Quantum Gravity and the Hardest Problem in Physics
 15:27: No real quantum states means no information except, perhaps, whatever information you need to track the bulk properties, like vacuum energy.


20171129: Citizen Science + ZeroPoint Challenge Answer
 06:57: ... a simplistic theoretical estimate of the vacuum energy density comes from assuming that there are no virtual photons above a ...
 07:06: ... frequency corresponding to a photon with the Planck energy, you get a vacuum energy density of a ridiculously high 10 to the power of 112 ergs per ...
 07:18: In this theoretical estimate, vacuum energy density is proportional to the fourth power of cutoff frequency.
 07:59: And if vacuum energy is proportional to the fourth power of cutoff frequency, then this equation gives the relationship we need.
 08:07: There are a bunch of constants in the cutoff frequency vacuum energy relation, but they cancel out.
 08:32: ... the right maximum virtual photon frequency definitely can't give us the vacuum energy that we see as dark ...


20171122: Suicide Space Robots
 12:46: Hawking radiation is related to this whole vacuum energy virtual particle thing.


20171108: ZeroPoint Energy Demystified
 00:14: Let's talk about what vacuum energy really can and really can't do.
 00:53: ... our observations of the accelerating expansion of the universe suggest a vacuum energy density of only 10 to the power of minus 8 ergs per centimeter ...
 01:05: ... this mismatch between the measured and theoretical values of vacuum energy is one of the greatest unsolved problems in ...
 01:35: ... source to manipulating it to generate warp fields or pushing against the vacuum energy in propulsionalist space ship ...
 04:02: In order to access vacuum energy, we need to introduce a disequilibrium.
 04:08: In fact, we need to reduce the vacuum energy in one region of space.
 04:31: By cutting off certain frequency modes between the plates, you lower the vacuum energy in that region.
 05:18: Well, if we define the average vacuum energy as 0, then the Casimir Effect produces negative energy.
 05:26: Unfortunately, the vacuum energy between Casimir plates is very much positive in an absolute sense.
 05:36: That means the vacuum energy between Casimir plates still produces positive spatial curvature, not the negative curvature required for warp drives.
 06:59: Vacuum energy is real, and it's part of the fundamental clockwork of the universe.
 07:56: Geckos literally manipulate quantum vacuum energy to climb walls.
 08:35: ... as we saw last week, the theoretical density of the vacuum energy due to the electromagnetic field is estimated by integrating the energy ...
 08:48: You get that the vacuum energy density is proportional to the fourth power of that cutoff frequency.
 08:55: Based on the vacuum energy density, as we've already talked about, answer me this.


20171102: The Vacuum Catastrophe
 01:26: Let's talk about vacuum energy from a theoretical standpoint.
 02:42: We'll get back to whether the idea of an infinite vacuum energy is actually possible.
 03:31: ... if we add up the vacuum energy, including virtual photons, all the way up to the Planck energy, we get a ...
 03:49: ... enough energy to boil all of the oceans on the planet, yet even if vacuum energy did have a value this high in fact, even if it were infinite we may ...
 04:23: As long as the vacuum energy is the same everywhere, then it's inaccessible to us as an energy source.
 04:39: Long story short a crazily high, even infinite, vacuum energy doesn't affect the predictions of quantum field theory.
 05:07: Vacuum energy should produce a gravitational effect, and a huge vacuum energy should produce a huge gravitational effect.
 05:37: ... down that rabbit hole if you haven't already, but the upshot is that, if vacuum energy really did have the enormous value predicted by theory, then our gently ...
 06:25: It gives particles a supersymmetric counterpart that may precisely cancel out their vacuum energy.
 06:32: ... down to the socalled electroweak energy, which brings the predicted vacuum energy down to a mere 10 to the 47 ergs per centimeter ...
 06:52: For a while, theorists assumed that something like this must be happening, meaning the vacuum energy was really 0.
 07:09: ... is, in fact, accelerating in exactly the way we'd expect from a nonzero vacuum energy. ...
 07:20: ... of accelerating expansion allows us to measure the absolute density of vacuum energy. ...
 07:31: Assuming vacuum energy is to blame, dark energy weighs in at 10 to the power of negative 8 ergs per centimeter cubed.
 07:59: ... can give us an extremely high vacuum energy or a vacuum energy of exactly 0 if we assume symmetry of positive and ...
 11:05: Vacuum energy can't be used as a power source.


20171025: The Missing Mass Mystery
 11:21: A nonzero vacuum energy would have a gravitational effect.
 11:34: So enough vacuum energy could result in a closed, rather than infinite, universe.
 11:39: And rather differently to regular matter, vacuum energy doesn't dilute in an expanding universe.


20171019: The Nature of Nothing
 07:40: ... physicist Hans Bethe successfully explained it in terms of a fluctuating vacuum energy. ...
 08:34: It should have vacuum energy.
 08:51: ... any nonresonant virtual photon would be excluded, reducing the vacuum energy between the ...
 09:11: The higher vacuum energy outside, compared to the inside of the plates, should result in a pressure differential that pushes the plates together.
 09:42: Now while there are potentially other explanations for the observed force, this has been taken as strong evidence that vacuum energy is real.
 09:51: Neither the Casimir effect nor the Lamb shift allow measurement of the absolute strength of vacuum energy.
 10:05: So how much vacuum energy is there?
 10:18: Dark energy itself may be vacuum energy.
 10:22: ... so, then the amount of vacuum energy needed to produce the observed acceleration is tiny, around one one ...
 10:33: And the theoretical calculation of the strength of the vacuum energy is a little higher than that.
 10:53: ... in all of science, and yet it's prediction of the strength of the vacuum energy seems to be wildly ...


20171011: Absolute Cold
 06:21: For example, the quantum fields that fill our universe also fluctuate due to the Uncertainty Principle resulting in what we know as vacuum energy.


20170628: The First Quantum Field Theory
 09:40: ... fields in the socalled hyperfine splitting or spins interacting with vacuum energy fluctuations in the lamb ...


20170621: AntiMatter and Quantum Relativity
 14:02: ... vacuum field can have one or more local minima, where the vacuum energy can come to a rest in an eternally inflating spacetime, halting ...
 14:14: The vacuum energy may come to a rest at different minima in different bubbles or it can be a false vacuum in one and the true vacuum in the other.
 14:38: ... the high energy bubble, it's much worse because that change in the vacuum energy state would propagate at the speed of light to fill that universe, ...


20170607: Supervoids vs Colliding Universes!
 09:13: In particular, its vacuum energy takes on a stable value.


20160518: Antigravity and the True Nature of Dark Energy
 02:03: A constant cosmological constant represents a nonzero energy of empty space, a vacuum energy.
 02:18: OK, the big, weird fact about a constant vacuum energy density is that leads to exponential expansion.


20160427: What Does Dark Energy Really Do?
 07:36: This lets us interpret the cosmological constant as representing a sort of vacuum energy, a property of space itself.
 07:48: But why should a constant vacuum energy cause the universe to accelerate?


20160420: Why the Universe Needs Dark Energy
 08:04: ... density of regular matter will, at some point, drop below that of this vacuum energy, as described by the cosmologicalconstant ...


20151028: Is The Alcubierre Warp Drive Possible?
 06:02: Quantum scale manipulation of the vacuum energy a la the Casimir effect may be enough.
