algorithm:
A fullyspecified procedure for solving a mathematical problem (such as
finding the greatest common divisor of two numbers) in a finite number of
steps, often involving repetition of an operation.
angular momentum:
For a particle, the cross product of the vector from a specified
reference point to the particle and the particle's linear momentum; for
an assembly of particles, the sum of the individual angular momentums.
avalanche photodiode:
A photodiode operated in the avalanche breakdown region to achieve
internal photocurrent multiplication, thereby providing rapid
lightcontrolled switching operation. A photodiode is a semiconductor
diode in which the reverse current varies with illumination.
basis:
A reference system for measuring a physical property, such as
a horizontal/vertical frame for measuring photon polarization.
Bell's Theorem:
A theorem stating that for any collection of objects with three different
properties, A, B, and C, the number of objects that have property A but
not property B plus the number of objects which have property B but not
property C is greater than or equal to the number of objects which have
property A but not property C.
breakdown voltage:
The voltage measured at a specified current in the electrical breakdown
region of a semiconductor diode. Electrical breakdown is a large, usually
abrupt, rise in electric current in the presence of a small increase in voltage.
cipher:
1. A method of transforming texts character by character in
order to conceal their meaning. 2. Such transformed messages.
CODE:
A method of transforming texts by substituting words or phrases according
to an agreed dictionary or codebook.
coherent light:
Radiant electromagnetic energy of approximately the same wavelength with
fixed phase relationships between different points in the field.
conjugate bases:
Two bases oriented so that a measurement in one randomizes the
measurement in the other.
cryptogram:
A communication in cipher or code.
cryptotext:
In cryptology, a text of visible writing which conveys no intelligible
meaning, or conveys an intelligible meaning that is not the real meaning.
decrypting:
The converting (as a coded message) into intelligible form by
decodeing or deciphering.
electron avalanche:
The cumulative process in which an electron accelerated by a strong
electric field collides with and ionizes gas molecules, thereby releasing
additional electrons that in turn have more collisions, so that the
discharge is selfmaintained.
encodeing:
The conversion of a message or body of information into coded form.
encrypting:
Converting a message or body of information into an obscured form using a
cipher or CODE.
hole:
A vacant electron energy state near the top of an energy band in a
solid. It behaves as though it were a positively charged particle, and is
also known as electron hole. An energy band is a restricted range in
which the energies of electrons in solids lie, or from which they are
excluded, as understood in quantum mechanical terms.
key:
In cryptology, a set of parameters used in conjunction with an encrypting
algorithm.
key distribution problem:
The problem of two parties agreeing on a secure key in a way that
cannot be learned by eavesdroppers.
ntype semiconductor:
An extrinsic semiconductor in which the conduction electron density
exceeds the hole density.
pn junction:
The interface between two regions in a semiconductor crystal which have
been treated so that one is a ptype semiconductor and the other is an
ntype semiconductor.
ptype semiconductor:
An extrinsic semiconductor in which the hole density exceeds the
conduction electron density.
plaintext:
Readable information that is to be encrypted.
prime number:
An integer greater than 1 with no positive integer divisors other than 1
and itself; e.g., 2, 3, 5, 7, 11, 13, 17, and 19 are prime
numbers.
quantum:
1. For certain physical properties such as energy or momentum, a
fundamental unit such that the property appears in integer multiples of
the unit. 2. An elementary particle carrying one unit of the property. For
example, the photon is the quantum of the electromagnetic field, carrying
an energy equal to Planck's contant times the frequency of the light and
an angular momentum equal to a multiple of Planck's constant divided by
2p.
quantum computation:
Computation by exploitation of the quantum mechanical nature
of particles such as electrons or atomic nuclei. This property is used to
enCODE information as quantum bits, or qubits, which can take on the
values of 0 or 1 or both at the same time.
quantum computer:
A proposed computer that would exploit the quantum mechanical nature of
particles, such as electrons or atomic nuclei, to manipulate
information as quantum bits, or qubits. Whereas an ordinary bit has at
any time a value of either 0 or 1, a qubit can also take on both values
at once. Because a quantum computer can act on these multiple states
simultaneously, it is potentially many times as powerful as a
conventional computer.
quantum theory:
The modern theory of discretized matter, electromagnetic radiation, and
interaction between matter and radiation. It generalizes and
supersedes classical physics, mainly in the realm of atomic and subatomic
phenomena. Also known as quantum mechanics.
qubit:
A basic unit of quantum information, representing either 0 or 1
but capable of being carried by a particle in both states until
measured or resolved.
vacancy:
A defect in the form of an unoccupied lattice position in a crystal.
