=Paper=
{{Paper
|id=Vol-2561/paper3
|storemode=property
|title=Introduction to Quantum Development
|pdfUrl=https://ceur-ws.org/Vol-2561/paper3.pdf
|volume=Vol-2561
|authors=Jose Luis Hevia Oliver
|dblpUrl=https://dblp.org/rec/conf/quanswer/Oliver20
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==Introduction to Quantum Development==
https://ceur-ws.org/Vol-2561/paper3.pdf
Introduction to Quantum Development
Jose Luis Hevia Oliver
1 Alhambra, Madrid, 28037, Spain 2
Jluis.hevia@a-e.es
Abstract. Brief presentation to introduce to the Quantum basics needed to un-
derstand the Quantum Computing Principles.
Keywords: Quantum Computer, Quantum Mechanics, Qubits.
1 Quantum Computing introduction
We live an amazing moment of the history, again: we are living the
raise of the quantum computers. We have been spectators of the birth and
evolution of exciting technologies related to digital information and it’s
process: from oldest x86 first IBM 16bits to the most powerful i7 x64
multicore processors; from the first gross mobile phone to the most ad-
vanced smartphones; from modem and copper communications cable to
5g internet or optical fiber and true high speed; and a lot of discovers we
cannot talk about in one paper. All these technologies working together
has made possible an incredible world of opportunities, thanks in large
measure to the features that bring us the software and the computers.
But in the era in which we live, there are still challenges that not even
the most modern computers can help us solve in a reasonable time. All
this challenges must be attended in order to solve a lot of uses cases that
could make the human raise, move forward a new step in its own evolu-
tion: discover news ways to create energy sources that reduces drastically
the climate change, discover new materials, discover new molecular
combinations to create better drugs or treatments to ill people…and
much more. We have a lot of process force to analyze business data…
but we don´t have enough power to analyze the nature.
In this context is where quantum computers appear to the rescue.
Quantum Computers that make possible the usage of the fundamental
part of the nature, to know more about the nature; that can give us a
power of computation never seen before; and that require us a new way
to address the problems.
Copyright © 2020 for this paper by its authors. Use permitted under Creative Commons
License Attribution 4.0 International (CC BY 4.0).
32
The principles of a Quantum computer are based on Quantum Mechanics! And these
principles are like magic. For a long time, brilliant physicist had been trying to explain
the marvel behavior of the light particles. And most of the main theories and experi-
ments have these principles in common: Matter at Quantum level can be found simul-
taneously in multiple and different configurations (states). That is known as superposi-
tion. Also, these states could interfere with others like waves in a pond. And some of
these states could be connected with others, in such a way that if one changes its state,
the other also. Giving to us the entanglement’s principle. But not everything is as beau-
tiful as it seems. These states can be observed but –and this is a big problem- the ob-
servation alters reality (collapse). A good starting point to know more about that is the
experiment of the Schrodinger’s cat and the Heisenberg‘s uncertainty principle. We
have all the possible realities in our hands, but in the moment we need to access it, it
collapses into a single reality.
Thanks to these principles, quantum computers provides to us the
qubits. These “magical artifacts”, makes possible the access a power of
computation never seen before. Qubits makes possible the use of a power
that is not simply but exponential (see Fig. 1). When a classical bit can
store one value (0 or 1) at a time, the qubit can handle 0,1 or both at same
time. So, a quantum computer with N cubits can process at least 2n states
at the same time.
So, for example –applying a reduce version of the travels man prob-
lem-, if we have N=1,000,000 possible routes from Bogotá, Colombia to
Lima, where Peru is the fastest one. To find the optimum route, a com-
puter must start by digitalizing 1,000,000 options. While Classical com-
puter need to analyze the routes one by one, the quantum computer can
consider all the routes at the same time. Classical computer needs n/2
steps (500.00 attempts) while Quantum computer can perform entire op-
eration in only √N steps (1.000 attempts).
33
Fig. 1. Bits an qubits comparison
But, in this magic world, there exists challenges that must be solve in
order to make real the use of all this power. Not everything is “easy”.
Due to the inherent properties of the hardware and the kind of matter that
must be controlled, the Quantum Decoherence Obstacle represent the
loose of the Quantum properties when an experiment is run in a specific
period of time. At the same time, and again due to the properties of the
quantum world, we need to fight with Quantum errors. Energy, temper-
ature, noise, gates, magnetic fields…even the inherent entropy of quan-
tum world have a direct impact on Qubits behavior, its quality and its
usefulness. The Error rate represents the operating time versus
34
decoherence time. If it is small enough it’s possible to correct the errors.
A lot of work must be done in this particular field.
The quantum computers can be implemented in different ways de-
pending on subjacent technologies to obtain the qubits (Superconduct-
ing, Trapped ION, Optical Lattices, Majorana Fermion particles), pur-
pose (general purpose, specific solutions) and types (topological, adia-
batic, one way…).
The state of the art: quantum race to obtain a topological computer
with lots of qubits and, of course, most of them quality qubits.
Fig. 2. Evolution of quantum computer power
Complex quantum computers, known as topological quantum comput-
ers, uses the concept of Quantum Gates. A collection of basic operations
used to interact with the features of the qubits. In this kind of computers,
quantum gates make possible the design, process and execution of cir-
cuits. These gates are a black box that encapsulate the complexity of the
underground mathematics. The names of the gates: Identity, Hadamard
(H Gate), Pauli-X, Pauli-Y, Pauli-Z, Square root of NOT (NOT), Phase
Shift, SWAP, Square root of SWAP, Controlled (cX, cY, cZ), Toffoli
(CCNOT) and CSWAP.
Using combinations of these gates, it’s possible to have the quantum
principles in our hands, for example:
• Hadamard gate give us the superposition effect
• And hadamard in combination with the CNOT using two qubits,
give us the entanglement effect.
35
To explore the magic and power of the quantum computers, some bril-
liant companies offers to the engineers, distributed quantum platforms
and tools that let them interact with the top quantum computers or pow-
erful simulators available today. Examples of this amazing companies
are IBM –with Quantum Experience-, Microsoft –with Quantum SDK
and Azure- and Dwave –with ocean SDK-.
These amazing technologies give us the possibility to create quantum
circuits or quantum programs -high level code using programming lan-
guages- that interacts with real machines or simulators through the soft-
ware stack. Examples of that:
1) Using the quantum SDK of Microsoft to test the superposition:
operation BellTest (count : Int, initial: Result) : (Int, Int)
{
mutable numOnes = 0;
using (qubit = Qubit()) {
for (test in 1..count) {
Set (initial, qubit);
H(qubit);
let res = M (qubit);
// Count the number of ones we saw:
if (res == One) {
set numOnes += 1;
}
}
Set(Zero, qubit);
}
// Return number of times we saw a |0> and number of
times we saw a |1>
return (count-numOnes, numOnes);
}
2) Using the Q Composer of IBM or its Python alternative to test the
entanglement:
36
Fig. 3. Example of quantum program execution
# Load account data from Opened Session Info
provider = IBMQ.load_account()
# Create a 2 QuBits and 1 Classical Bit –collapse meassure-
Quantum Circuit
qcBell = QuantumCircuit(2, 1)
qcBell.h(0)
qcBell.cx(0, 1)
qcBell.measure(0,0)
qcBell.draw()
# Prepare the execution and get the results
job = execute(qcBell,
backend=Aer.get_backend('qasm_simulator'),
parameter_binds=[])
counts = [job.result().get_counts(i) for i in range(len(job.re-
sult().results))]
print (counts)
37
In both cases, we have the opportunity to create, compile, execute and
debug the code. And experiment all the amazing possibilities this incred-
ible technology can bring us in the future… today.
Welcome to the Quantum new era.
References
1. Jose Luis Hevia: Quantum Computing Fundamentals, Course Materials. Alhambra Sys-
tems & M2i Formacion. URL: https://www.m2iformacion.com/Cur-
sos/DetalleCurso.aspx?idcurso=M2iESPQ001
2. Feynman, R. P. "Simulating Physics with Computers" International Journal of Theoretical
Physics, Vol. 21 (1982) pp. 467-488.
3. Nielsen, M. y Chuang, I. "Quantum Computation and Quantum Information" Cambridge
University Press (September, 2000), ISBN 0-521-63503-9.Author, F.: Contribution title. In:
9th International Proceedings on Proceedings, pp. 1–2. Publisher, Location (2010).
4. Simon Benjamin: The Dawn of Quantum Technology. Oxford Quantum for Oxford Univer-
sity. URL: https://www.youtube.com/watch?v=7wThe1Q95Ro from http://oxfordquan-
tum.org.
5. Vladimir-Silva: Practical Quantum Computing for Developers (Apress-2019)
6. Eleanor Rieffel: An Introduction to Quantum Computing for Non-Physicists (FX Palo Alto
Labs)
7. O’Reilly: Programming Quantum Computers Essential Algorithms and Code Samples