Warp Drives - Revision history

Lwcamp: /* Alcubierre warp interactions with light and matter */

2026-04-07T05:34:06Z

Alcubierre warp interactions with light and matter

← Older revision		Revision as of 22:34, 6 April 2026
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	=== Alcubierre warp interactions with light and matter ===		=== Alcubierre warp interactions with light and matter ===

	Space is not entirely empty. It is filled with a diffuse plasma in the form of the interstellar medium, as well as cosmic radiation, light from stars, and cosmic microwave background radiation. A warp drive propagating through space will encounter this stuff. ~~When~~ happens when this matter and radiation have a warp bubble pass across them?		Space is not entirely empty. It is filled with a diffuse plasma in the form of the interstellar medium, as well as cosmic radiation, light from stars, and cosmic microwave background radiation. A warp drive propagating through space will encounter this stuff. What happens when this matter and radiation have a warp bubble pass across them?

	The first analysis of matter encountering a warp bubble was performed by Pfenning and Ford<ref name="PfenningFord_2001"></ref>. They looked at the warp bubble interaction with a massive object at rest with the frame of reference of the warp drive (keep in mind that the rest frame is the same inside and outside the warp bubble; in this rest frame objects inside the bubble have no momentum even though they are, in some sense, changing location rapidly with time). When the warp bubble passes, the object experiences an acceleration in the direction of the warp bubble motion. When the warp shell passes and the object is inside the bubble, it will be moving with approximately the speed of the bubble. Pfenning and Ford analyzed this problem with a continuous distribution of shell energy that, strictly speaking, never falls to zero except at the bubble center and at spatial infinity, so unless the object passes through the center in Pfenning and Ford's description it will never <i>quite</i> get up to the bubble's speed. In this case, the object will move almost as fast as the object but will pass through the bubble in a finite time, after which it will again be at rest with respect to the reference frame but displaced along the direction of the warp bubble motion by some distance. With this description of the warp bubble, a spacecraft of finite size will always be moving a little slower than the warp bubble and would have to use rockets to keep up with it. in addition, the spacecraft would experience tidal forces that would cause stress on the spacecraft's structure.		The first analysis of matter encountering a warp bubble was performed by Pfenning and Ford<ref name="PfenningFord_2001"></ref>. They looked at the warp bubble interaction with a massive object at rest with the frame of reference of the warp drive (keep in mind that the rest frame is the same inside and outside the warp bubble; in this rest frame objects inside the bubble have no momentum even though they are, in some sense, changing location rapidly with time). When the warp bubble passes, the object experiences an acceleration in the direction of the warp bubble motion. When the warp shell passes and the object is inside the bubble, it will be moving with approximately the speed of the bubble. Pfenning and Ford analyzed this problem with a continuous distribution of shell energy that, strictly speaking, never falls to zero except at the bubble center and at spatial infinity, so unless the object passes through the center in Pfenning and Ford's description it will never <i>quite</i> get up to the bubble's speed. In this case, the object will move almost as fast as the object but will pass through the bubble in a finite time, after which it will again be at rest with respect to the reference frame but displaced along the direction of the warp bubble motion by some distance. With this description of the warp bubble, a spacecraft of finite size will always be moving a little slower than the warp bubble and would have to use rockets to keep up with it. in addition, the spacecraft would experience tidal forces that would cause stress on the spacecraft's structure.

Lwcamp: /* The Alcubierre warp drive */

2026-03-13T17:49:59Z

The Alcubierre warp drive

← Older revision		Revision as of 10:49, 13 March 2026
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	<td>The expansion of space in the warp shell of an Alcubierre drive, assuming an infinitesimally thin shell. Negative expansion means that space is contracting in that direction, positive expansion that it is expanding.		<td>The expansion of space in the warp shell of an Alcubierre drive, assuming an infinitesimally thin shell. Negative expansion means that space is contracting in that direction, positive expansion that it is expanding.
	</table>		</table>

			NOTE: What the? The energy distribution is symmetric! How does the drive know which way to go? There must be significant contributions of other components of the stress-energy tensor, and those have got to be asymmetric along the forward/backward axis. Check this when I get time.

	Almost as soon as Alcubierre proposed his warp drive, others began picking it apart.		Almost as soon as Alcubierre proposed his warp drive, others began picking it apart.

Lwcamp: /* Lentz warp drive */

2026-03-12T15:46:23Z

Lentz warp drive

← Older revision		Revision as of 08:46, 12 March 2026
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	Quick notes (will expand on later): Santiago, Schuster, and Visser<ref name="Santiago Schuster Visser 2022">J. Santiago, S. Schuster, and M. Visser, "Generic warp drives violate the null energy condition", Physical Review D <b>105</b>, 064038 (2022) https://doi.org/10.1103/PhysRevD.105.064038</ref> dispute claims that the Lentz drive satisfies the energy conditions, noting that everywhere positive energy density in one frame of reference is insufficient to establish that the energy density is positive in all reference frames; knowledge of the Cauchy stress tensor is also needed. They show that any generic warp drive will violate the strong energy condition, null energy condition, and weak energy condition.		Quick notes (will expand on later): Santiago, Schuster, and Visser<ref name="Santiago Schuster Visser 2022">J. Santiago, S. Schuster, and M. Visser, "Generic warp drives violate the null energy condition", Physical Review D <b>105</b>, 064038 (2022) https://doi.org/10.1103/PhysRevD.105.064038</ref> dispute claims that the Lentz drive satisfies the energy conditions, noting that everywhere positive energy density in one frame of reference is insufficient to establish that the energy density is positive in all reference frames; knowledge of the Cauchy stress tensor is also needed. They show that any generic warp drive will violate the strong energy condition, null energy condition, and weak energy condition.

			Santiago, Schuster, and Visser<ref name="Santiago Schuster Visser 2022"></ref> also claim the Lentz drive is a subset of the Fell-Heisenberg drive.

	== Fell-Heisenberg warp drives ==		== Fell-Heisenberg warp drives ==

Lwcamp: /* Fell-Heisenberg warp drives */

2026-03-12T14:48:50Z

Fell-Heisenberg warp drives

← Older revision		Revision as of 07:48, 12 March 2026
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	Natário zero expansion drive is divergenceless; the Fell-Heisenberg drive is irrotational. Opposite choices of the typical decomposition of a vector field here!		Natário zero expansion drive is divergenceless; the Fell-Heisenberg drive is irrotational. Opposite choices of the typical decomposition of a vector field here!

	Despite the introduction discussing warp drive configurations that satisfy the various energy conditions, the configurations described in the paper are shown to locally violate the weak and strong energy conditions. Nonetheless, the energy density is still <i>mostly</i> positive.		Despite the introduction discussing warp drive configurations that satisfy the various energy conditions, the configurations described in the paper are shown to locally violate the weak and strong energy conditions. Nonetheless, the energy density is still <i>mostly</i> positive. Santiago, Schuster, and Visser's<ref name="Santiago Schuster Visser 2022"></ref> work shows claims that the various energy conditions must still be violated by this warp drive; to not violate these, energy density must be positive in all reference frames not just those of the co-moving observer.

	The energy needed to form a Fell-Heisenberg drive is about 10,000 times less than the mass-energy of our sun. Or only about half the mass-energy of Jupiter. A significant improvement over other proposed drives.		The energy needed to form a Fell-Heisenberg drive is about 10,000 times less than the mass-energy of our sun. Or only about half the mass-energy of Jupiter. A significant improvement over other proposed drives.

Lwcamp: /* Lentz warp drive */

2026-03-12T14:46:56Z

Lentz warp drive

← Older revision		Revision as of 07:46, 12 March 2026
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	(stuff goes here)<ref name="Lentz">E. W. Lentz, "Breaking the warp barrier: hyper-fast solitons in Einstein–Maxwell-plasma theory", Classical and Quantum Gravity. <b>38</b> 075015 (2021). arXiv:[https://arxiv.org/abs/2006.07125 2006.07125]. Bibcode:[https://ui.adsabs.harvard.edu/abs/2021CQGra..38g5015L 2021CQGra..38g5015L]. doi:[https://doi.org/10.1088%2F1361-6382%2Fabe692 10.1088/1361-6382/abe692]. ISSN [https://search.worldcat.org/issn/0264-9381 0264-9381]. S2CID [https://api.semanticscholar.org/CorpusID:219635854 219635854].</ref>		(stuff goes here)<ref name="Lentz">E. W. Lentz, "Breaking the warp barrier: hyper-fast solitons in Einstein–Maxwell-plasma theory", Classical and Quantum Gravity. <b>38</b> 075015 (2021). arXiv:[https://arxiv.org/abs/2006.07125 2006.07125]. Bibcode:[https://ui.adsabs.harvard.edu/abs/2021CQGra..38g5015L 2021CQGra..38g5015L]. doi:[https://doi.org/10.1088%2F1361-6382%2Fabe692 10.1088/1361-6382/abe692]. ISSN [https://search.worldcat.org/issn/0264-9381 0264-9381]. S2CID [https://api.semanticscholar.org/CorpusID:219635854 219635854].</ref>

			Quick notes (will expand on later): Santiago, Schuster, and Visser<ref name="Santiago Schuster Visser 2022">J. Santiago, S. Schuster, and M. Visser, "Generic warp drives violate the null energy condition", Physical Review D <b>105</b>, 064038 (2022) https://doi.org/10.1103/PhysRevD.105.064038</ref> dispute claims that the Lentz drive satisfies the energy conditions, noting that everywhere positive energy density in one frame of reference is insufficient to establish that the energy density is positive in all reference frames; knowledge of the Cauchy stress tensor is also needed. They show that any generic warp drive will violate the strong energy condition, null energy condition, and weak energy condition.

	== Fell-Heisenberg warp drives ==		== Fell-Heisenberg warp drives ==

Lwcamp: /* Fell-Heisenberg warp drives */

2026-03-12T14:30:42Z

Fell-Heisenberg warp drives

← Older revision		Revision as of 07:30, 12 March 2026
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	Natário zero expansion drive is divergenceless; the Fell-Heisenberg drive is irrotational. Opposite choices of the typical decomposition of a vector field here!		Natário zero expansion drive is divergenceless; the Fell-Heisenberg drive is irrotational. Opposite choices of the typical decomposition of a vector field here!

	Despite the introduction discussing warp drive configurations that satisfy the various energy conditions, the configurations described in the paper are shown to locally violate the weak and strong energy conditions.		Despite the introduction discussing warp drive configurations that satisfy the various energy conditions, the configurations described in the paper are shown to locally violate the weak and strong energy conditions. Nonetheless, the energy density is still <i>mostly</i> positive.

	The energy needed to form a Fell-Heisenberg drive is about 10,000 times less than the mass-energy of our sun. Or only about half the mass-energy of Jupiter. A significant improvement over other proposed drives.		The energy needed to form a Fell-Heisenberg drive is about 10,000 times less than the mass-energy of our sun. Or only about half the mass-energy of Jupiter. A significant improvement over other proposed drives.

Lwcamp: /* Fell-Heisenberg warp drives */

2026-03-12T03:32:11Z

Fell-Heisenberg warp drives

← Older revision		Revision as of 20:32, 11 March 2026
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	First example I've seen yet with a non-zero ADM mass.		First example I've seen yet with a non-zero ADM mass.

			Natário zero expansion drive is divergenceless; the Fell-Heisenberg drive is irrotational. Opposite choices of the typical decomposition of a vector field here!

			Despite the introduction discussing warp drive configurations that satisfy the various energy conditions, the configurations described in the paper are shown to locally violate the weak and strong energy conditions.

			The energy needed to form a Fell-Heisenberg drive is about 10,000 times less than the mass-energy of our sun. Or only about half the mass-energy of Jupiter. A significant improvement over other proposed drives.

	(<i>n. b.</i> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)		(<i>n. b.</i> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)

Lwcamp: /* Fell-Heisenberg warp drives */

2026-03-12T02:58:42Z

Fell-Heisenberg warp drives

← Older revision		Revision as of 19:58, 11 March 2026
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	(stuff goes here)<ref name="Fell-Heisenberg">S. D. B. Fell and L> Heisenberg, "Positive energy warp drive from hidden geometric structures", Classical and Quantum Gravity <b>38</b> 155020 (2021) https://doi.org/10.1088/1361-6382/ac0e47 https://arxiv.org/abs/2104.06488</ref>		(stuff goes here)<ref name="Fell-Heisenberg">S. D. B. Fell and L> Heisenberg, "Positive energy warp drive from hidden geometric structures", Classical and Quantum Gravity <b>38</b> 155020 (2021) https://doi.org/10.1088/1361-6382/ac0e47 https://arxiv.org/abs/2104.06488</ref>

			Quick notes: vanishing momentum everywhere. Yet the energy occupies regions where the shift vector is varying rapidly. The lack of momentum means that the energy will not move to keep up with the differential expansion and movement of the spacetime. As a consequence, at later times the energy will have a different distribution than what is necessary to maintain the given warp configuration; exact time evolution is not solved but likely leads to collapse of warp bubble.

			First example I've seen yet with a non-zero ADM mass.

	(<i>n. b.</i> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)		(<i>n. b.</i> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)

Lwcamp: /* Fell-Heisenberg warp drives */

2026-03-08T21:39:08Z

Fell-Heisenberg warp drives

← Older revision		Revision as of 14:39, 8 March 2026
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	(stuff goes here)<ref name="Fell-Heisenberg">S. D. B. Fell and L> Heisenberg, "Positive energy warp drive from hidden geometric structures", Classical and Quantum Gravity <b>38</b> 155020 (2021) https://doi.org/10.1088/1361-6382/ac0e47 https://arxiv.org/abs/2104.06488</ref>		(stuff goes here)<ref name="Fell-Heisenberg">S. D. B. Fell and L> Heisenberg, "Positive energy warp drive from hidden geometric structures", Classical and Quantum Gravity <b>38</b> 155020 (2021) https://doi.org/10.1088/1361-6382/ac0e47 https://arxiv.org/abs/2104.06488</ref>

	(<i>n. b.</> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)		(<i>n. b.</i> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)

	== Conservation laws ==		== Conservation laws ==

Lwcamp: /* Lentz warp drive */

2026-03-08T21:38:56Z

Lentz warp drive

← Older revision		Revision as of 14:38, 8 March 2026
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	(stuff goes here)<ref name="Lentz">E. W. Lentz, "Breaking the warp barrier: hyper-fast solitons in Einstein–Maxwell-plasma theory", Classical and Quantum Gravity. <b>38</b> 075015 (2021). arXiv:[https://arxiv.org/abs/2006.07125 2006.07125]. Bibcode:[https://ui.adsabs.harvard.edu/abs/2021CQGra..38g5015L 2021CQGra..38g5015L]. doi:[https://doi.org/10.1088%2F1361-6382%2Fabe692 10.1088/1361-6382/abe692]. ISSN [https://search.worldcat.org/issn/0264-9381 0264-9381]. S2CID [https://api.semanticscholar.org/CorpusID:219635854 219635854].</ref>		(stuff goes here)<ref name="Lentz">E. W. Lentz, "Breaking the warp barrier: hyper-fast solitons in Einstein–Maxwell-plasma theory", Classical and Quantum Gravity. <b>38</b> 075015 (2021). arXiv:[https://arxiv.org/abs/2006.07125 2006.07125]. Bibcode:[https://ui.adsabs.harvard.edu/abs/2021CQGra..38g5015L 2021CQGra..38g5015L]. doi:[https://doi.org/10.1088%2F1361-6382%2Fabe692 10.1088/1361-6382/abe692]. ISSN [https://search.worldcat.org/issn/0264-9381 0264-9381]. S2CID [https://api.semanticscholar.org/CorpusID:219635854 219635854].</ref>

			== Fell-Heisenberg warp drives ==

			(stuff goes here)<ref name="Fell-Heisenberg">S. D. B. Fell and L> Heisenberg, "Positive energy warp drive from hidden geometric structures", Classical and Quantum Gravity <b>38</b> 155020 (2021) https://doi.org/10.1088/1361-6382/ac0e47 https://arxiv.org/abs/2104.06488</ref>

			(<i>n. b.</> The Heisenberg here is Lavinia Heisenberg, not the Werner Heisenberg of quantum physics and uncertainty principle fame.)

	== Conservation laws ==		== Conservation laws ==