‘Quantum Computing: Separating Hope from Hype’ Saturday 4th September, 10am PST
The talk will explain why quantum computers are useful, and also dispel some of the myths about what they can and cannot do. It will address some of the practical ways in which we can build quantum computers and give realistic timescales for how far away commercially useful systems might be.
Dr Suzanne Gildert is currently working as an Experimental Physicist at D-Wave Systems, Inc. She is involved in the design and testing of large scale superconducting processors for Quantum Computing Applications. Suzanne obtained her PhD and MSci degree from The University of Birmingham UK, focusing on the areas of experimental quantum device physics and superconductivity.
Previous work from Dr Gildert was an attempt to estimate the amount of computational speedup that the current Dwave adiabatic quantum computers are able to achieve. Some existing calculations are ten thousand times faster than classical systems.
This seminar will explain the fundamental concepts of the Quantum Computer (QC) and how these systems might be able to perform certain tasks that classical computers find incredibly difficult. The different models of quantum computing will be introduced and the advantages and disadvantages of each described. A promising model known as Adiabatic Quantum Computing (AQC) will be discussed, an approach which can be applied to some very interesting problems in a wide variety of fields: Biology, microprocessor design, pharmaceuticals, economics, transport, chemistry and business. The talk will also examine some case studies of industrial applications in these fields where QC may be extremely useful.
There will be a review of some of the experimental challenges involved in building QCs, and a focus on a particularly promising version known as the ‘superconducting flux qubit processor’. The devices involved in this type of QC are fabricated using a process similar to semiconductor technology, but using Niobium and Aluminum rather than Silicon as the device materials. There will be a brief overview of the physics which causes these devices to demonstrate ‘macroscopic quantum coherence’- an effect which allows us to scale up quantum effects to a size where we can manipulate them easily, and why the devices must be cooled to millikelvin temperatures for them to work properly.
The power of quantum computing is often skewed by the media, with quantum computers being hailed as ‘futuristic’ replacements for desktop machines, whereas the reality is that they are very specialized machines, and therefore more like fast co-processors. The talk will therefore also describe the limitations of quantum computers, both in theory and in terms of what can be practically built
What quantum computers cannot do
You can never ‘see’ a superposition of states. So you need an algorithm that uses the quantum superpositions to calculate a classical answer without ‘disturbing it’.
You can only read out a CLASSICAL answer (Quantum Measurement problem).
This is the tricky bit – the algorithm must be able to find and somehow ‘amplify’
the correct answer amongst the superpositions, so that when you take a
measurement you are likely to get the right answer
They can’t solve all problems exponentially faster than classical computers. For
most computational tasks they are useless!
● Shor’s algorithm for factoring has an exponential speedup
● Grover’s algorithm for searching only has a Quadratic speedup
But this can still help for large problem sizes
But they might not always be so specialised – New quantum algorithms are being
A Family of Quantum Computers
There is more than one way to make a quantum computer.
Depending upon which way you make it determines what problems it can
Lots of people ask questions like:
How many qubits?
What decoherence time?
Think about an analogue computer vs. a digital one, or a programmable
logic chip vs. a general purpose computer.
● Gate model – ‘Standard ‘ model
● Adiabatic Quantum Computation – a close contender
● Cluster state (measurement based) – slightly more obscure
● Topological quantum computing – slightly more obscure
From 2009- Dr Gildert personally believed that we will start to see applications of quantum computing in 5-10 years time (funding and result dependent).
Potential Quantum computer Application Areas
In this video talk, she indicates that Dwave Systems should get to commercial applications over the next few years with their adiabatic quantum computers and the gate model could get their in 10 years. She thinks the superconducting implementations will lead the way and then ion trap QC and then nitrogen vacancy.
Engineering: Circuit routing Microprocessor/ASIC design Product and component placement Traveling Salesman problem Network Routing Congestion simulation Systems Biology: Metabolomic pathways Metabolite databases Bioinformatics Genetics Biochemistry Matching gene sequences Searching sequence and databases Protein folding Nano-Physics: Spin system modeling Molecular manufacturing Chemistry/Physics Simulating energy levels Quantum systems Security and Internet Cryptography Biometrics Image recognition & processing Database and www searching Fast scanning of network traffic AI Machine learning Neural networks