SF Props: FTL And "Phase Velocity"

"...while the group velocity of a particle-wave train is limited to that of light, the phase velocity is not. Accordingly, in this 'future history' the invention of a device for handling discontinuous psi functions permits a spaceship to assume a pseudo-velocity (not a true speed in the mechanical sense) limited only by the frequency of the engine's oscillators."
-Poul Anderson, Virgin Planet (London, 1966), "Author's Note," pp. 150-156 AT p. 150.

(These psi functions are not connected with ESP.)

See:

Another Means Of FTL
STL Or FTL?
FTL II
Alternative Quantum Mechanics

This "phase velocity" FTL in Anderson's Psychotechnic History differs from the "quantum jump" FTL in his Technic History although there are similar references to "pseudo-velocity" and to oscillator frequencies.

In James Blish's pantropy series, Okie series and The Quincunx Of Time, modulated phase velocity is used to send messages faster than light along a connecting beam of light-speed radiation. The Okies also have the instantaneous Dirac transmitter and the Service in Quincunx additionally has an application of the Dirac that enables reception of messages from the past and future as well as the present.

In Poul Anderson's "Time Patrol," both instantaneous travel and time travel require infinitely discontinuous functions. Thus, there are conceptual connections between several series.

Two Background Details

Poul Anderson, Virgin Planet (London, 1966), Author's Note, pp. 150-156.

"...the philosophical pantheism of Cosmos..." (p. 151)

"...phase velocity..." (p. 150) explains FTL travel as, in James Blish's "Beep"/The Quincunx Of Time, it explains FTL communication.

"...discontinuous psi functions..." (ibid.) are also involved in FTL and we are told elsewhere that "...infinitely discontinuous functions..." (Time Patrol, p. 9) are involved both in instantaneous transportation and in travel to the past.

James Blish and the Time Patrol are frequent sources of comparisons when discussing Poul Anderson's future histories.

Two Kinds Of FTL And One Of Time Travel?

 

In "Gypsy":

"The principles of the hyperdrive are difficult enough, involving as they do the concept of multiple dimensions and of discontinuous psi functions." (p. 20)

But, in "The Pirate":

"...once [another spaceship] went over to the tachyon mode, only a weak emission of super-light particles was available." (p. 219)

- "available" for tracking purposes.

Sound like two completely different means of faster than light travel although in the same future history series?

Elsewhere in space and time:

"'...discontinuity is entirely possible.'"

-Poul Anderson, "Time Patrol" IN Anderson, Time Patrol (Riverdale, NY, December 2010), pp. 1-53 AT 2, p. 10.

This speaker replies to someone who, he says, insists on:

"'...only continuous functions.'" (ibid.)

He is talking about time travel but it sounds like the "Gypsy" account of FTL.

All of this is inside Poul Anderson's multiverse, however.

Virgin Planet

"Virgin Planet" by Poul Anderson was:

published in Venture Science Fiction, 1957;
novelized in 1959;
republished in the Anderson collection, Starship (New York, 1982), pp. 83-181.

In my copy of Virgin Planet (London, 1966), the text of the novel is on pp. 9-149. Thus, 41 more pages, with smaller, closer print, than the shorter version in Venture and Starship. Pp. 150-156 are an Author's Note, explaining the premises of the novel:

the light speed limit applies to "...the group velocity of a particle-wave train..." but not to phase velocity so "...a device for handling discontinuous psi functions..." (p. 150) allows a faster than light pseudo-velocity "...limited only by the frequency of the engine's oscillators" (ibid.) and also gravity control;

a spatial condition called a trepidation vortex, as explained in the novel, can occur;

"...a nearly perfect dielectric..." (p. 151) makes small, manageable blaster guns feasible (an earlier story in this, Psychotechnic, future history mentioned "dielectrics" as making destructive weapons feasible for smaller groups and I commented that this idea should reappear as part of the background of later installments);

electronic readjustment of emotional patterns;
robots;
interstellar emigration for psychological, not economic, reasons;
the Stellar Union and its Coordination Service;
a Basic language and a Cosmic religion;
the galaxy mapped with reference to constellations as seen from base planets like Nerthus.

This background information might be more interesting than the story although I will shortly reread the latter, at least in the shorter version. One difference that I remember between the two versions is that one of them shows Lesbianism within the women only colony whereas the other does not.

Trepidation Vortices

In Poul Anderson's "Gypsy," the faster than light spaceship, the Traveler, carrying colonists from Earth to Alpha Centauri, suffers an explosion in its engines and winds up thousands of light-years away, unable to find home. To explain the mishap, crew members speculate about space warps, "...points of infinite discontinuity, unidimensional fields, and Cosmos knows what else." (Starship, New York, 1982, p. 20)

The phrase "...Cosmos knows..." acknowledges that there is a Cosmic religion in this future history although I am not sure that its tenets are elucidated anywhere in the series?

Three other works explain the phenomenon that threw the Traveler off course: a trepidation vortex. The Author's Note to Virgin Planet informs us that such vortices are consistent with the postulated physics of the series. "Virgin Planet" and The Peregrine present, respectively, shorter and longer dictionary definitions of a trepidation vortex and Virgin Planet summarizes the Manual on the subject.

Combining these three accounts, such vortices are:

(i) traveling regions of warped space;
causes of violently shifting gravitational fields;
responsible for planetary perturbations;
able to displace and, usually, destroy a spaceship on hyperdrive.
 
(ii) large traveling force-fields of uncertain origin and nature;
causes of gravitational turbulence with gyromagnetic and electric side-effects;
similar to hydrodynamic vortices;
causes of trepidation in material bodies and of irregularities in hyperdrive fields, either destroying a ship or throwing it off course;
possibly caused by local concentrations of nascent mass.

(iii) little understood traveling sections where the geometry of the continuum is distorted;
able, if big enough, to make a planetary rotation period fluctuate by a few seconds;
able to destroy or displace a spaceship on hyperdrive if the ship's discontinuous psi functions mesh with those of the vortex.

We can see that Anderson has an idea and tries out different ways to express it.

Tachyons

"The Pirate."

A spaceship in the normal mode can be tracked by:

amplified sight;

thermal radiation;

radar;

neutrinos from its powerplant.

- on the tachyon mode by:

"...a weak emission of super-light particles..." (p. 219)

When Trevelyan Micah and Smokesmith in the Genji followed Murdoch Juan and his crew in their Campesino, Murdoch's crew detected the Genji's tachyons while faster-than-light and her neutrinos while slower-than-light.

Tachyons are faster-than-light particles. (Theoretical, as yet.) When in the tachyon mode, a spaceship emits super-light particles/tachyons. But what is the "tachyon mode"? Are the ship and its contents transformed into tachyons? Or, at least, are they endowed with whatever property of tachyons makes them move faster than light?

Have there been two hyperdrives in the Psychotechnic History, the first involving multiple dimensions and discontinuous psi functions, as in "Gypsy," and the second involving tachyons, as in "The Pirate"?

Who can possibly say?

Gaps

When the short story, "Gypsy," introduces the hyperdrive in Poul Anderson's Psychotechnic History, we are told that the principles of the drive involve multiple dimensions and discontinuous psi functions. Thus, this is not the multiple quantum jumps hyperdrive of the same author's later Technic History.

In a future history series, the author might develop a near future period and a further future period, leaving a chronological gap between them. In Robert Heinlein's Future History, "Logic of Empire" shows indentured servitude on Venus while a Prophet gains support in the US whereas the succeeding installment, "If This Goes On -," shows a US theocracy that has caused a hiatus in space travel. We have not seen the First Prophet come to power although we are about to see one of his successors overthrown. Perhaps seventy years - as well as three "stories-to-be-told" - occupy the gap between the two installments.

The gap in Poul Anderson's Psychotechnic History is much longer, 545 years according to the Chronology. In "Brake," human beings have spread through the Solar System but there is turmoil on Earth. In "Gypsy," human beings are spreading at faster then light speeds beyond the Solar System but the hyperspace ship, Traveler, is lost and its crew have settled on an Earth-like planet that they call "Harbor."

I am currently rereading "Gypsy" and have not yet found any internal evidence that it belongs in the same future history. In fact, when does the FTL period of the history make clear that it connects with the STL period?

The Chronology reads:

2270  "Brake"
2300  The  Second Dark Ages
2600
2784  Hyperdrive invented
2815  "Gypsy"
           Nomad culture develops  

So what happened in 2600 that we are not told about? It must be something to do with the restoration of civilization after the Second Dark Ages but it is not the founding of the Stellar Union because that comes later:

2875  "Star Ship"
2900  Stellar Union and Coordination Service founded

The Coordinators begin less than a century after the Nomads.