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hja379
- Master | Next Rank: 500 Posts
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Please take a look at this passage and help answer the question. It seemed very tough and I couldn't still understand even after reading the explanation.
A quantum computer operates on a principle similar to
that of a classical computer: an array of "switches" are each
either "on" or "off." How then could a quantum computer
perform a complex calculation in seconds when a classical
(5) computer would take years to solve the same problem?
The answer lies in the bizarre physics of the subatomic world
as defined by quantum mechanics, in which an atom may exist
in a state of superposition, in which, in effect, it exists in two
states at once. Thus, the "switch" in a quantum computer,
(10) unlike the electronic switch in a classical computer, is not just
"on" or "off" but could also be both at the same time.
Some quantum computers use the charge of electrons in a
helium atom as the computational "switch." Others use
trapped ions. But the most "typical" quantum computer
(15) makes use of the spin state of the electron in a hydrogen
atom. A spin-based quantum computer would consist of a
number of "contained" hydrogen atoms as well as the means
of control -- in other words, the device that would contain
the atom, read its spin as either "spin up" or "spin down,"
(20) and also be able to change its spin. Each atom and its
"containment field" are defined as one computational unit, a
qubit, or quantum bit.
The quantum computer owes a debt to a man who may
have doubted its existence to be possible, the physicist Edwin
(25) Schrodinger. Studying the atomic decay of radioactive
particles on a quantum level, Schrodinger proclaimed
something must be wrong with the mathematics. The
calculations seemed to suggest that two answers were
possible at any given time, the superposition which is the
(30) basis of quantum computation. To show the absurdity of this
outcome, Schrodinger created a thought experiment.
Imagine a cat that is in a box and cannot be observed. Also
in the box is a syringe of poison which will be injected into
the cat, causing the feline to die. The trigger for the syringe
(35) is the same process of atomic decay which Schrodinger had
been calculating. A scientist uses the math of quantum
physics to determine at what point the syringe is activated
and the cat dies. What the scientist discovers, however, is
that, according to the mathematics, at any given point the cat
(40) is both alive and dead. Schrodinger had no idea that he had
just designed the world's first quantum computer.
Question
The passage suggests that the spin state of a hydrogen atom is analogous to what aspect of Schrodinger's thought experiment?
Choices
A - the box that the cat is contained in
B - the poison-filled syringe
C - the mathematical calculations that the scientist must make
D - the process of atomic decay
E - the observation that the cat is both alive and dead at any given moment
OA D
A quantum computer operates on a principle similar to
that of a classical computer: an array of "switches" are each
either "on" or "off." How then could a quantum computer
perform a complex calculation in seconds when a classical
(5) computer would take years to solve the same problem?
The answer lies in the bizarre physics of the subatomic world
as defined by quantum mechanics, in which an atom may exist
in a state of superposition, in which, in effect, it exists in two
states at once. Thus, the "switch" in a quantum computer,
(10) unlike the electronic switch in a classical computer, is not just
"on" or "off" but could also be both at the same time.
Some quantum computers use the charge of electrons in a
helium atom as the computational "switch." Others use
trapped ions. But the most "typical" quantum computer
(15) makes use of the spin state of the electron in a hydrogen
atom. A spin-based quantum computer would consist of a
number of "contained" hydrogen atoms as well as the means
of control -- in other words, the device that would contain
the atom, read its spin as either "spin up" or "spin down,"
(20) and also be able to change its spin. Each atom and its
"containment field" are defined as one computational unit, a
qubit, or quantum bit.
The quantum computer owes a debt to a man who may
have doubted its existence to be possible, the physicist Edwin
(25) Schrodinger. Studying the atomic decay of radioactive
particles on a quantum level, Schrodinger proclaimed
something must be wrong with the mathematics. The
calculations seemed to suggest that two answers were
possible at any given time, the superposition which is the
(30) basis of quantum computation. To show the absurdity of this
outcome, Schrodinger created a thought experiment.
Imagine a cat that is in a box and cannot be observed. Also
in the box is a syringe of poison which will be injected into
the cat, causing the feline to die. The trigger for the syringe
(35) is the same process of atomic decay which Schrodinger had
been calculating. A scientist uses the math of quantum
physics to determine at what point the syringe is activated
and the cat dies. What the scientist discovers, however, is
that, according to the mathematics, at any given point the cat
(40) is both alive and dead. Schrodinger had no idea that he had
just designed the world's first quantum computer.
Question
The passage suggests that the spin state of a hydrogen atom is analogous to what aspect of Schrodinger's thought experiment?
Choices
A - the box that the cat is contained in
B - the poison-filled syringe
C - the mathematical calculations that the scientist must make
D - the process of atomic decay
E - the observation that the cat is both alive and dead at any given moment
OA D
Last edited by hja379 on Thu Jan 20, 2011 10:58 am, edited 2 times in total.
