The quantum mechanic, Q, is a monster in Nethack, and the only member of the Q quantum mechanic monster class. It has an attack that causes its target to teleport when it hits; the teleport is subject to magic cancellation, permits you to use teleport control, and will fail on non-teleport levels.
Quantum mechanics are humanoid but are not considered human, so they will respect Elbereth, and human player characters will not be penalized for cannibalism by eating a quantum mechanic corpse. They are poisonous to eat, however, and doing so will toggle intrinsic speed - granting it if you do not have it, and removing it if you already possess it.
There is a 5% chance that a quantum mechanic carries a large box. Upon opening the box, with a 50% chance a peaceful housecat named "Schroedinger's Cat" is generated; if generation or 50% chance fails, the box will contain a cat corpse named "Schroedinger's Cat". The state of the cat is not determined until the box is opened; in fact, the large box is effectively empty until opened. The housecat has no special properties, and is simply based on a well-known thought experiment in quantum physics. See the article for more specific information.
Quantum mechanics do not hit particularly hard themselves, but the teleportation will cause you no end of annoyance outside areas like Sokoban. It can also place you in a much more disadvantageous position than you were previously, e.g. by teleporting you away from the stairs in large open areas, separating you from your pets, or else placing you next to a particularly nasty monster. If teleported out of a shop, the shopkeeper will be angered if you have any unpaid items on hand; be sure to establish credit beforehand if possible. As a pet, the quantum mechanic has some relative use since it can teleport away many other monsters, but can also teleport shopkeepers out of their shops if their level is high enough, which angers them.
Eating a quantum mechanic corpse is a useful way to gain the speed intrinsic, but should be avoided while you have it; you can tin them to reapply the intrinsic speed if it is lost, e.g. from the attacks of a cockatrice, green slime, or shade. While the same can be done with a wand of speed monster, this allows you to save more of its charges for pets, especially after Orcus-town; use a stethoscope to keep track of your own speed.
The monster's name is a pun on "Quantum Mechanics", a branch of physics. The messages that accompany the monster's teleporting attack and the toggling of intrinsic speed are jokes based on the Heisenberg uncertainty principle, which states that measuring the position of a particle makes its velocity more uncertain, and vice versa. Toggling the speed intrinsic could also be a reference to the transitions that occur between discrete energy levels in quantum mechanics.
Schrödinger's cat is a famous thought experiment in quantum mechanics involving imagining locking a cat in a box with a mechanism that has a 50% chance of killing the cat, depending upon the final state of a quantum system. The orthodox Copenhagen interpretation of quantum mechanics asserts that the cat in the box is in a superposition of possible outcomes; in half of them the cat is dead, and in the other half it is alive. Only when the box is opened and "observed" is the quantum wavefunction collapsed and the fate of the cat determined; Schrödinger asserted that this was absurd, and thus so was the Copenhagen interpretation. Modern physicists are still divided on its validity.
- Your position suddenly seems very uncertain!
- A quantum mechanic hit you and you attempted to teleport.
- Having determined the quantum mechanic's speed, you are unable to know its location.
- You applied a stethoscope to a quantum mechanic and received a message of its status.
- Your velocity suddenly seems very uncertain!
- You ate a quantum mechanic corpse and your intrinsic speed is about to be toggled.
- You seem slower.
- Your intrinsic speed was toggled off.
- You seem faster.
- Your intrinsic speed was toggled on.
These creatures are not native to this universe; they seem
to have strangely derived powers, and unknown motives.
_Uncertainty Principle_ The principle that it is not possible
to know with unlimited accuracy both the position and momentum
of a particle. ... An explanation of the uncertainty is that
in order to locate a particle exactly, an observer must be
able to bounce off it a photon of radiation; this act of
location itself alters the position of the particle
in an unpredictable way. To locate the position accurately,
photons of short wavelength would have to be used. The high
momentum of such photons would cause a large effect on the
position. On the other hand, using photons of lower momenta
would have less effect on the particle's position, but would
be less accurate because of the lower wavelength.
[ A Concise Dictionary of Physics ]