We show that with the addition of multiple walkers, quantum walks on a line can be transformed into lattice graphs of higher dimension. Thus, multi-walker walks can simulate single-walker walks on higher dimensional graphs and vice versa. This exponential complexity opens up new applications for present-day quantum walk experiments. We discuss the applications of such higher-dimensional structures and how they relate to linear optics quantum computing. In particular we show that multi-walker quantum walks are equivalent to the BosonSampling model for linear optics quantum computation proposed by Aaronson & Arkhipov. With the addition of control over phase-defects in the lattice, which can be simulated with entangling gates, asymmetric lattice structures can be constructed which are universal for quantum computation.

In the setting of networked computation, data security can be a significant concern. Here we consider the problem of allowing a server to remotely manipulate client supplied data, in such a way that both the information obtained by the client about the server’s operation and the information obtained by the server about the client’s data are significantly limited. We present a protocol for achieving such functionality in two closely related models of restricted quantum computation — the Boson sampling and quantum walk models. Due to the limited technological requirements of the Boson scattering model, small scale implementations of this technique are feasible with present-day technology.

Multi-dimensional quantum walks can exhibit highly non-trivial topological structure, providing a powerful tool for simulating quantum information and transport systems. We present a flexible implementation of a 2D optical quantum walk on a lattice, demonstrating a scalable quantum walk on a non-trivial graph structure. We realized a coherent quantum walk over 12 steps and 169 positions using an optical fiber network. With our broad spectrum of quantum coins we were able to simulate the creation of entanglement in bipartite systems with conditioned interactions. Introducing dynamic control allowed for the investigation of effects such as strong non-linearities or two-particle scattering. Our results illustrate the potential of quantum walks as a route for simulating and understanding complex quantum systems.

In our work we demonstrate that even with very substantial loss rates (whether it be source inefficiency, loss within the circuit, or detector inefficiency), such a computer can likely perform calculations beyond the reach of any classical computer. This is great news for experimentalists, for whom photon loss is a killer in their experiments. Our results show that with enough single photon sources, even with a loss rate of 50% our optical quantum computer can likely do things that classical computers can’t. This is unlike fault-tolerance results for universal quantum computers, whereby loss rates of even 0.1% are a killer. This all sounds very optimistic, but there is one drawback – no one knows what to do with this particular type of quantum computer. Aaronson & Arkhipov show that such a device almost certainly can do things that a classical computer can’t, but no actual applications have been identified. So there’s a catch – building such a quantum computer, which can outperform all the classical computers in the world put together, is within reach of present-day technology, but, no one has any idea what to do with it.

I hope these results will stimulate further research into Aaronson & Arkhipov-type devices, which will hopefully come up with some useful applications – a killer application for BosonSampling would represent a major step forward for the field. In the meantime, I hope some of the experimental groups in the optical quantum computation community will think about elementary demonstrations of such systems. Simple extensions of present-day multi-photon quantum walk experiments (e.g. this work by Peruzzo et al., and this work by Owens et al.) could act as an elementary test-bed for such systems.

The region overlapped by red and blue is where we suggest a BosonSampling quantum computer is performing a classically intractable computation - plotted against the number of photon sources and the net single photon source/detection efficiency.

When someone gets a job at a business, they agree to do a certain amount of work for a certain amount of pay. It is not an agreement entered into solely on one side. It is not an agreement forced onto one side by the other. It is a voluntary, mutual agreement. I find it outrageous that, after entering an agreement voluntarily, that one side (in this case the unions) retrospectively decide that actually, on second thought, they want more than they agreed to. Then, to achieve that aim, they engage in strike action, with the aim of blackmailing the business by threatening them with bankruptcy if they don’t acquiesce. This is extortion.

Imagine that you hired someone to help clean your house, and you agreed to pay them $10 an hour to help you out. Then, a few weeks later they turn up outside your house with a bunch of mates, threatening signs and refusing to work unless you agree to $20 an hour. Would you (a) give them $20 an hour, or (b) fire them an hire someone else who is willing to do the work they agreed to do? This example precisely reflects what’s happening in the union movement around the world.

You might say, why not give them $20 an hour – they’d be better off, it’s only fair? The answer is, simply, that it drives unemployment. Why employ one person for $20 an hour when you can employ two for $10? Thus, the activities of unions effectively act as a driving force for unemployment.

Those in support of unions frequently claim that unions are there to represent workers. This couldn’t be further from the truth. Unions do not represent workers, they represent paying members. Therefore, those who are not represented by the unions, and I’m specifically referring to the unemployed, get no representation whatsoever and lose out. I’d rather have solidarity with someone who is unemployed and priced out of a job, than someone with a job and a comfy lifestyle, who simply wants more.

Indeed, it is questionable whether union activity even benefits the members. When people earn more money without a corresponding increase in productivity, people have more money with which to buy goods, but the amount of goods hasn’t changed. This is inflation. When inflation occurs the RBA responds by increasing interest rates, which means that everyone is paying more on their mortgage, more on their car loan, more on their credit card, and no one is better off.

Some hardline critics of unions advocate banning unions as a solution to the problem. This solution involves taking away people’s freedom of association. So, how do we prevents these kinds of activities without taking away freedom? By giving more. Specifically, employers should be allowed to discriminate against employees on the basis of union membership. They should have the right to say “we’ll employ you, provided that you don’t join the union and engage in strike action”, and negotiate these terms into the employment contract. Secondly, because industrial action amounts to extortion, employers should be free to fire employees engaging in that kind of action and litigate for losses. This solution addresses the problem, without depriving anyone of inalienable rights.

I hope the outcome with Qantas strengthens the public’s skepticism of the union movement and opens people’s eyes to the true nature of collective action. It’s time society recognised the true face of unions. They are not there to help people out or make sound economic decisions. They are there to accumulate power into the hands of union bosses and thugs so they can later run for public office and become a minister (or undemocratically overthrow a Prime Minister). This needs to stop.

Read full paper here.

Listen to and download Die for Belief here on Jamendo.

There are most certainly Israeli government policies of which I am critical. I criticise the Israeli government for not being as pro-active as it could be in regard to finding a solution for peace with the Palestinians. What I object to however is exaggerated and discriminatory criticism. I find, ever increasingly, particularly amongst the so-called ‘intellectual elite’ in Australian society (i.e. academics with an overinflated sense of self-importance, who consider themselves the pinnacle of mankind’s intellectual achievement) that criticism of Israel is disproportionate and rife, hypocritical and downright discriminatory. Sure, I don’t agree with everything that Benjamin Netanyahu says or does, but does this really justify a widespread, concerted international effort to criticise, demonise and undermine Israel? Aren’t there other countries more deserving of criticism than Israel? Why is there an all-out effort to attack Israel, on the basis of territorial disputes and counter-terrorism efforts, when there are so many other wrongs in the world? Why do we have organisations like this one, why are there proposed labour union-sponsored academic boycotts in the UK, and why is our own Australian electorate of Marrickville proposing a total boycott of all Israeli products, when there are so many others more worthy of criticism? The answer is, very plainly, that it’s discrimination and racism. People hate Israel. There, I said it – people hate Israel. Do the same organisations, unions and local councils suggest that we boycott China for oppressing Tibetans? No. Do they boycott Australia, the UK and the US for the wars against Iraq and Afghanistan (which I know they disagree with)? No. Do they boycott Iran for persecuting the minority Bahai faith, or Saudi Arabia for executing homosexuals and stoning so-called ‘adulterers’ (i.e. rape victims)? No. When criticism is due, give it, but keep it in proportion and keep it fair. The international movement against Israel is not founded on fact and objectivity – it is founded on hatred and discrimination. I don’t agree with everything Israel says and does, but the same applies to every other country on Earth. Singling out a single country, and repeatedly attacking them for policies we disagree with, while ignoring the huge injustices in so many other countries is discrimination, plain and simple.

In a region of the Earth ruled by tyrants, dictators and Islamist fundamentalists, Israel is the only modern, Western-style, progressive, parliamentary democracy. Israel is a multicultural society, with a huge Muslim minority (about 20%) , and even takes a world-leading social stance by recognising same-sex marriage. Do they get credit for this? No. Instead her critics choose to focus all their efforts on degrading her and insinuating that she is a racist apartheid country, while ignoring her strengths, and completely forgetting the injustices in so many other countries including their own.

If Israel is deserved of a boycott for her attempts to protect herself against terrorism, then so is Australia for its participation in the Iraq and Afghanistan wars. If Israel is criticised as an ‘apartheid country’, then we should look at our own – Israel has far larger ethnic minority groups than Australia does, all of whom have full democratic rights.

Israel is more like our own country than any other in that region of the World. Yet, there is an enormous international movement, led by the radical left and the ‘intellectual elite’, to demonise that country. Before you make a concerted effort to alienate Israel, take a long, hard look at your own country.

If you gave me a choice to live in any country in the Middle Eastern region, I know where I’d prefer to live, without a shadow of a doubt – and it wouldn’t be the country where they amputate my hands for opposing the rulers or stone to death my wife for being raped.

Dear Editor,

Please find attached our manuscript “Entanglement dynamics and quasi-periodicity in discrete quantum walks” for consideration for rejection from The Journal of Universal Rejection. In this paper we study the use of the quantum walk formalism in the preparation of entangled states as a resource for other quantum information processing tasks. We show that, surprisingly, highly irregular, almost chaos-like dynamics emerge when boundary conditions are imposed on the graph on which the walk is taking place. As numerous experimental groups are beginning to experimentally demonstrate elementary quantum walks, our study is topical and relevant. We hope you will consider our paper for rejection.

Sincerely,

Dr. Peter P. Rohde
BE (Hons I), PhD

Dear Dr. Rohde,

Thank you for your submission “Entanglement dynamics and quasi-periodicity in discrete quantum walks” to the Journal of Universal Rejection.

A thorough review of your paper led us to the conclusion: revise and resubmit.  Here is what we would like to see:
* Perform a linear walk experiment on an infinite graph
* Put in a picture of the Bifurcation diagram of the logistic map, because that is cool, and
* Translate your paper into rhymed couplets.

Let me know if you should need further clarification about any of these suggestions.

Should you carry out the above steps, acceptance is not guaranteed. We will of course need to review your paper again.

Best regards,
Caleb

Dear Dr. Emmons,

Thank you for taking the time to review our manuscript. Regrettably our institution is undergoing funding cuts which will rule out the possibility of performing an experiment with an infinite sized graph. Thus we will be unable to satisfy the requirements of the reviewers.

Kind regards,

Peter Rohde.