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In-Depth Information
Table 10.1
The four
functions of a single binary
variable
x
i
g
0
g
1
g
2
g
3
0
0
0
1
1
1
0
1
0
1
Table 10.2
Procedure to
identify constant and
nonconstant functions
x
i
g
2
Prepared list
Tagged list
Assumed list structure
011
1
¼a
1
101
1
¼a
2
2
2
2
b
1
¼ð
1
η
Þ
p
þðη
Þð
q
Þ¼
1
2
η
¼
0
:
(10.5)
2
2
b
2
¼ð
1
η
Þ
p
ðη
Þð
q
Þ¼
1
:
(10.6)
2
[0 1]
0
which after sampling is 1 or true,
determinedwith certaintywith one sampling (or measurement). So a systemcan know
that the original vector is
1]
0
transforms to
1
Since
η
¼
0.5,
η
[1
¼
1)
0
without having to probe and perhaps disturb the
multivibrator. This transform is reversible. For example, [0 1]
0
may be transformed
to be [pq]
0
where p
η
(1
¼
0; q
¼
1/
η
, returning the vector to
b
¼ η
[1
1]
0
.
Binary Function Classification Involving One Simulated Qubit
Assuming an ordinary binary function of a single bit, possibilities are, the function
is constant: either g(x
i
)
¼
0org(x
i
)
¼
1 for i
¼
1, 2; (note that x
1
¼
0, x
2
¼
1)
x
i
0
, the complement of x
i
.
This information is presented in a truth table, Table
10.1
.
Two functions, g
0
and g
3
, are constant functions as x
i
varies; the other two, g
1
and g
2
, are nonconstant.
Recall that simulated qubits have at their core a set of multivibrator waveforms
operating at a certain frequency and phase. A multivibrator function is a sequence
of rotations, polar and azimuthally, of the probability vector that introduces nega-
tive signs into the presampled output possibilities. For example, two simulated
qubits [a
1
a
2
]
0
,[b
1
b
2
]
0
may be prepared to be [1 1]
0
,[11]
0
meaning that each has
50 % probability of being true and 50 % probability of being false. Overall there are
finite probabilities for the following combinations a
1
b
1
, a
1
b
2
, a
2
b
1
, a
2
b
2
.
A multivibrator function is defined to be one that places a negative sign on one
more of these terms.
Generalizing, for any number of simulated qubits, the locations of the negative
signs are congruent to the 1s of a particular Boolean function. Negative signs are
invisible in the readout method, so with simple sampling fails to identify the
multivibrator function should it be unknown. A special procedure is required to
identify or at least classify the function. For example, refer to the inverter function,
g
2
, in Table
10.2
.
otherwise it is nonconstant: either g(x
i
)
¼
x
i
or g(x
i
)
¼
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