<p>Tunneling isn't possible, because the event horizon isn't a &quot;forbidden region&quot; with &quot;permitted regions on both sides&quot;.  In tunnelling you have  a potential wall.  Classical particles can't get over the wall, as they don't have enough energy to climb it, but quantum particles have a wavefunction with non-zero values on both sides of the wall, so there is a certain probability of moving from one side to the other</p>
<p>An event horizon, however, is not like a wall, but like a slope that goes up and keeps going up.  A particle inside the event horizon is in a potential well. It not only forbidden from travelling to the horizon, but from travelling to any point beyond it. There are no points at the same potential outside the black hole for to tunnel to (except in another black hole?)</p>
<p>Exotic particles could fall into black holes, just like everything else. From our viewpoint they never actually reach the event horizon.</p>
<p>As for 4. The is no real difference between &quot;particles&quot; and &quot;Energy&quot;  All energy is quantised into particles.  All particles carry a certain amount of mass and momentum, which is energy.</p>
<p>And regarding 5.  &quot;Dark Energy&quot; isn't really &quot;Energy&quot;, probably. It appears as a component of the total Mass/Energy of the universe, but may just be a property of space and not something like &quot;light&quot; or &quot;heat&quot;.</p>

CC BY-SA 4.0
2021-06-24T11:41:58.343Z
Isn't a slope that goes up and up the same as a potential wall? Or do you think the wall is infinitely high? Hawing radiation can tunnel through this wall. Or does it originste exactly on the horizon?
Deschele Schilder
CC BY-SA 4.0
2021-06-24T20:10:59.407Z
It is different becuuse it never comes down on the other side
James K
CC BY-SA 4.0
2021-06-24T06:04:41.130Z
2021-06-24T06:04:41.130Z
James K
<p>There could be particles smaller than electrons. Electrons are pictured as strucureless point particles but this is only probed to a certain distance (about 10exp(-18) meter). Inside the hole they will all mix up (in time as well as in space).</p>
<p>Only at the horizon particles are created. Hawking radiation. This is the same kind of process as from which matter was created in the early universe (the difference being that initially particles were created from negative curvature while in black holes positive curvature is involved).</p>
<p>Dark energy is associated with negative curvature. The stuff that produces this curvature is very different from normal stuff. It could indeed be exotic matter if you consider that to be a vacuum with negative energy (or negative mass(. This is not what comes out of a black hole though.</p>

CC BY-SA 4.0
2021-06-24T20:20:30.230Z
"Dark energy is associated with negative curvature" -- no, it is not.
"It could indeed be exotic matter if you consider that to be a vacuum with negative energy (or negative mass(" -- Again, no. (You could in principle have a vacuum with negative energy -- but we measure the dark energy to be *positive*, so if it *is* vacuum energy (e.g. the cosmological constant) then it is positive.)
Peter Erwin
CC BY-SA 4.0
2021-06-24T20:42:06.550Z
@PeterErwin Dark energy gives rise to negative curvature. It's a negative energy or negative mass (contrary to positive mass/energy that gives rise to positive curvature). And precisely on a negatively curved spacetime particles move away from esch other.
Deschele Schilder
CC BY-SA 4.0
2021-06-24T21:08:50.017Z
The measured value of the dark energy density is $\sim 6 \times 10^{-27}$ kg/m$^{3}$, or $\sim 3$ GeV/m$^{3}$ (see e.g. https://en.wikipedia.org/wiki/Cosmological_constant#Positive_value). This is a *positive* value. Please stop thinking it is "negative energy or negative mass"; it is not.
Peter Erwin
CC BY-SA 4.0
2021-06-24T21:25:43.420Z
@PeterErwin Energy density is always positive. Even if the energy is negative.
Deschele Schilder
CC BY-SA 4.0
2021-06-24T21:29:34.243Z
@PeterErwin Thats the weird stuff about dark enerģy . It can be negative (its like negative mass ; negative mass acts opposite to positive mass).
Deschele Schilder
CC BY-SA 4.0
2021-06-24T21:32:29.497Z
I admit to being curious as to why you think a negative value (e.g. energy) divided by a positive value (volume) would yield a positive value. This is basic arithmetic you're violating.
Peter Erwin
CC BY-SA 4.0
2021-06-24T21:40:06.743Z
The energy density is defined as the square of thr energy divided by the volume The root of the square that is. So always positive.
Deschele Schilder
CC BY-SA 4.0
2021-06-24T21:48:59.927Z
You have been misinformed. Energy density is energy divided by volume, period. (Mass density is mass divided by volume. Charge density is charge divided by volume. And so forth.)
Peter Erwin
CC BY-SA 4.0
2021-06-24T22:08:45.623Z
@PeterErwin Okay. In Gr e energy is defined as $E^{2}=m^{2}+p^{2}$. Then the root is taken.
Deschele Schilder
CC BY-SA 4.0
2021-06-24T22:50:28.343Z
@PeterErwin So the energy density can be positive while the pressure (due to negative momentum) can be negative. Negative pressure gives rise to negative curvature which gives ride to accelerated motion away from each other (the growing balloon models is quite misleading).
Deschele Schilder
CC BY-SA 4.0
2021-06-24T08:35:59.650Z
2021-06-24T08:35:59.650Z
Deschele Schilder
<ol>
<li>Quantum tunneling starts happening when there are empty energy states available for the electrons to occupy and the energy barrier is of the order of the wavefunction of the electrons.</li>
<li>Could there be exotic particles much smaller than electrons inside the black hole ?</li>
<li>If so, then the applying the same principle of available empty energy states outside of the blackhole, the 'exotic electron' can just disappear from within blackhole.</li>
<li>Also, it would not really emerge as a 'particle'. Since, blackholes are so efficient at converting the mass to energy -&gt; It would emerge as Energy</li>
<li>And could this be the source of Dark Energy that is ripping the universe ?</li>
</ol>

CC BY-SA 4.0
2021-06-24T06:05:02.087Z
See https://physics.stackexchange.com/questions/482651/quantum-tunneling-through-the-event-horizon-eh-is-the-eh-a-potential-barrier
James K
<black-hole><dark-energy><quantum-mechanics><white-hole><exotic-matter>
Can Quantum tunneling be possible within Blackhole ? And if so, could that be the source of Dark Energy?
Rajarshi Shukla
# Can Quantum tunneling be possible within Blackhole ? And if so, could that be the source of Dark Energy?

(Asked by: username_0 on 2021-06-24)

1. Quantum tunneling starts happening when there are empty energy states available for the electrons to occupy and the energy barrier is of the order of the wavefunction of the electrons.
2. Could there be exotic particles much smaller than electrons inside the black hole ?
3. If so, then the applying the same principle of available empty energy states outside of the blackhole, the 'exotic electron' can just disappear from within blackhole.
4. Also, it would not really emerge as a 'particle'. Since, blackholes are so efficient at converting the mass to energy -> It would emerge as Energy
5. And could this be the source of Dark Energy that is ripping the universe ?

**Tags:** black-hole, dark-energy, quantum-mechanics, white-hole, exotic-matter
> **Comments:**
> **username_1**: See https://physics.stackexchange.com/questions/482651/quantum-tunneling-through-the-event-horizon-eh-is-the-eh-a-potential-barrier  

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## 2 answers

### Answer by username_1 on 2021-06-24. Score: 1

Tunneling isn't possible, because the event horizon isn't a "forbidden region" with "permitted regions on both sides". In tunnelling you have a potential wall. Classical particles can't get over the wall, as they don't have enough energy to climb it, but quantum particles have a wavefunction with non-zero values on both sides of the wall, so there is a certain probability of moving from one side to the other

An event horizon, however, is not like a wall, but like a slope that goes up and keeps going up. A particle inside the event horizon is in a potential well. It not only forbidden from travelling to the horizon, but from travelling to any point beyond it. There are no points at the same potential outside the black hole for to tunnel to (except in another black hole?)

Exotic particles could fall into black holes, just like everything else. From our viewpoint they never actually reach the event horizon.

As for 4. The is no real difference between "particles" and "Energy" All energy is quantised into particles. All particles carry a certain amount of mass and momentum, which is energy.

And regarding 5. "Dark Energy" isn't really "Energy", probably. It appears as a component of the total Mass/Energy of the universe, but may just be a property of space and not something like "light" or "heat".

> **Comments:**
> **username_2**: Isn't a slope that goes up and up the same as a potential wall? Or do you think the wall is infinitely high? Hawing radiation can tunnel through this wall. Or does it originste exactly on the horizon?  
> **username_1**: It is different becuuse it never comes down on the other side  

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### Answer by username_2 on 2021-06-24. Score: -2

There could be particles smaller than electrons. Electrons are pictured as strucureless point particles but this is only probed to a certain distance (about 10exp(-18) meter). Inside the hole they will all mix up (in time as well as in space).

Only at the horizon particles are created. Hawking radiation. This is the same kind of process as from which matter was created in the early universe (the difference being that initially particles were created from negative curvature while in black holes positive curvature is involved).

Dark energy is associated with negative curvature. The stuff that produces this curvature is very different from normal stuff. It could indeed be exotic matter if you consider that to be a vacuum with negative energy (or negative mass(. This is not what comes out of a black hole though.

> **Comments:**
> **username_3**: "Dark energy is associated with negative curvature" -- no, it is not. "It could indeed be exotic matter if you consider that to be a vacuum with negative energy (or negative mass(" -- Again, no. (You could in principle have a vacuum with negative energy -- but we measure the dark energy to be *positive*, so if it *is* vacuum energy (e.g. the cosmological constant) then it is positive.)  
> **username_2**: @PeterErwin Dark energy gives rise to negative curvature. It's a negative energy or negative mass (contrary to positive mass/energy that gives rise to positive curvature). And precisely on a negatively curved spacetime particles move away from esch other.  
> **username_3**: The measured value of the dark energy density is $\sim 6 \times 10^{-27}$ kg/m$^{3}$, or $\sim 3$ GeV/m$^{3}$ (see e.g. https://en.wikipedia.org/wiki/Cosmological_constant#Positive_value). This is a *positive* value. Please stop thinking it is "negative energy or negative mass"; it is not.  
> **username_2**: @PeterErwin Energy density is always positive. Even if the energy is negative.  
> **username_2**: @PeterErwin Thats the weird stuff about dark enerģy . It can be negative (its like negative mass ; negative mass acts opposite to positive mass).  
> **username_3**: I admit to being curious as to why you think a negative value (e.g. energy) divided by a positive value (volume) would yield a positive value. This is basic arithmetic you're violating.  
> **username_2**: The energy density is defined as the square of thr energy divided by the volume The root of the square that is. So always positive.  
> **username_3**: You have been misinformed. Energy density is energy divided by volume, period. (Mass density is mass divided by volume. Charge density is charge divided by volume. And so forth.)  
> **username_2**: @PeterErwin Okay. In Gr e energy is defined as $E^{2}=m^{2}+p^{2}$. Then the root is taken.  
> **username_2**: @PeterErwin So the energy density can be positive while the pressure (due to negative momentum) can be negative. Negative pressure gives rise to negative curvature which gives ride to accelerated motion away from each other (the growing balloon models is quite misleading).  

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