Wednesday, September 29, 2010

Quantum model of the stock market

From arXiv recently: A quantum model of stock market by Zhang and Huang. The abstract:

Beginning with several basic hypotheses of quantum mechanics, we give a new quantum model in econophysics. In this model, we define the wave function and the operator of the stock market to establish the Schrodinger equation for the stock price. Based on this theoretical framework, an example of a driven infinite quantum well is considered, in which we use a cosine distribution to simulate the state of stock price in equilibrium. After adding an external field into the Hamiltonian to analytically calculate the wave function, the distribution and the average value of the rate of return are shown.

This one caught my eye and I figured it was worth mentioning since I work on financial web services for Xignite. It looks like the references would be a good place to start looking for other work using models of physics to study economics.

Entanglement of 3 out of 4 qubits in a superconducting system

Out of Nature: Entanglement of 3 out of 4 qubits in a superconducting system. Of course, others have done more than that, but superconducting systems seem to be more scalable- which means they have the possibility of being the first practical system.

Wednesday, September 8, 2010

Quantum Measurements Cannot be Proved to be Random

Another one from arXiv: Quantum Measurements Cannot be Proved to be Random by Rogers. At 4 pages a quick read and thought provoking.

Quantum Tagging with Cryptographically Secure Tags

I saw this on arXiv: Quantum Tagging with Cryptographically Secure Tags by Kent. I have not read it, but sounds interesting from the abstract:

Various authors have considered schemes for {\it quantum tagging}, that is, authenticating the classical location of a classical tagging device by sending and receiving quantum signals from suitably located distant sites, in an environment controlled by an adversary whose quantum information processing and transmitting power is potentially unbounded. This task raises some interesting new questions about cryptographic security assumptions, as relatively subtle details in the security model can dramatically affect the security attainable. We consider here the case in which the tag is cryptographically secure, and show how to implement tagging securely within this model.