[Catalyst 2018]

Quantum Computing
A Leap Forward in Processing Power
W
e live in the information age, defined
by the computers and technology that
reign over modern society. Computer
technology progresses rapidly every year,
enabling modern day computers to process
data using smaller and faster components
than ever before. However, we are quickly
approaching the limits of traditional
computing technology.
Typical computers process
data with transistors. 1
Transistors act as tiny
switches in one of
two definite states:
ON or OFF. 2
These states are
represented
by binary digits
known as “bits,”
1 for ON and 0 for
OFF. 2 Combinations
of bits let us describe
more complex data,
which ultimately becomes
the basis for a computer.
For instance, a 2-bit computer
has four possible bit combinations at
any given time: 11, 10, 01, and 00. Every
additional bit doubles the number of
possible combinations and increases the
computer’s ability to store and process
data. 3 Shrinking the size of transistors
allows more transistors to fit on a single
chip, giving us greater processing power
per chip. However, modern transistors
are reaching the size of only a few atoms. 4
We will soon reach the physical limit to
how small and fast a transistor can be.
Since 1975, the computer chip industry
has followed Moore’s Law, the notion
that the number of transistors on a chip
will double every two years, but recently,
delays in advancements have caused some
to announce the death of Moore’s Law. 5
Though we may not be capable of making
transistors much smaller, we can push past
their limits with a new type of computer:
the quantum computer.
Quantum computers use quantum bits,
or “qubits,” rather than bits. Qubits are
incredibly tiny particles that experience
by Valerie Hellmer
Superposition
and entanglement
allow quantum
computers to process
data faster than
traditional
computers
quantum effects like superposition and
entanglement due to their small size. 2 A
qubit is in superposition when it is in a
combination of two states simultaneously.
So while a normal bit must be either 1 or
0, a qubit can be both 1 and 0. 2 This can
be difficult to imagine since it goes against
everything we encounter throughout our
lives; a flipped coin can either land on
heads or tails, not both sides
at once. Yet qubits seemingly
defy our reality and do just
that. A 2-qubit computer still
possesses the four original
bit combinations, only
now the qubits can
simultaneously hold
all four combinations. 6
The qubits have a
probability of being in
each of the four states,
but the qubits’ actual
combination is revealed only
after being observed, which
collapses the superposition. 6
Even stranger than superposition,
quantum entanglement is when
the state of one qubit affects the state of
another instantaneously over any distance. 7
For instance, if two qubits are entangled in
opposites states, then when
one qubit changes from 1 to
0, the other changes from
0 to 1 without any delay.
This switch allows
information to travel
incredibly quickly
in a quantum
computer. But
that is not all
entanglement
has to offer;
entanglement
also lets you receive
information on a group
of entangled qubits by
checking the state of only
one qubit. 3 Superposition
and entanglement allow quantum
computers to process data faster than
traditional computers such that a 56-qubit
computer would contain more processing
power than any traditional computer
A 56-qubit
computer would
contain more
processing power than
any traditional
computer ever
built
ever built. 8 This achievement is known
as quantum supremacy over traditional
computing--an impressive feat considering
modern supercomputers can perform
93,000 trillion calculations per second. 8-9
Today’s top tech companies are getting
incredibly close to the quantum supremacy
milestone.
IBM has been researching quantum
computers for over 35 years, and has
recently shown rapid progress. 2 In May
2016, IBM released access to a 5-qubit
quantum computer online, where anyone
can develop and run their own quantum
algorithms. 1 This quantum computer has
created opportunities for both scientists
and enthusiasts to interact with qubits and
has already been used for over 1.7 million
public experiments. 10 IBM then established
a new quantum computing division called
“IBM Q” in March 2017. 1 And more recently,
in January 2018, the company developed a
50-qubit quantum computer prototype. 10
While these computers cannot beat any
classical machine at present, IBM has their
vision set on a future powered through
quantum computing. 1
Another computer company, D-Wave
Systems, is known for advancing
quantum computing with
a different approach. The
company made headlines in
2013 by selling a 512-qubit
computer called the
D-Wave Two to NASA
and Google. 11 And in
2017, the company
released a 2000-qubit
computer called
the D-Wave 2000Q,
which can run certain
algorithms 100 million
times faster than an average
classical computer. 11-12 While
these numbers make it sound
as if D-Wave Systems has easily
achieved quantum supremacy, this is not
necessarily the case. D-Wave Systems’
computers have faced a lot of controversy
since they use a “quantum annealing”
16 | CATALYST