  Quantum computing is an emerging field of science which will eventually lead
us to new and powerful logic devices with capabilities far beyond the limits of
current transistor-based technology. There are certain types of problems which
quantum computers can solve fundamentally faster than the tradition digital
computers. There are quantum algorithms which require both superposition and
entanglement (e.g. Shor algorithm). But neither the Grover algorithm nor the
very first quantum algorithm due to Deutsch and Jozsa need entanglement. Is it
possible to utilize classical wave superposition to speedup database search?
This interesting question was analyzed by S. Lloyd. It was concluded that
classical devices that rely on wave interference may provide the same speedup
over classical digital devices as quantum devices. There were several
experimental works using optical beam superposition for emulating Grover
algorithm. It was concluded that the use of classical wave superposition comes
with the cost of exponential increase of the resources. Since then, it is
widely believed that the use of classical wave superposition for quantum
algorithms is inevitably leading to an exponential resources overhead (number
of devices, power consumption, precision requirements). In this work, we
describe a classical Oracle machine which utilizes classical wave superposition
for database search and data processing. We present experimental data on
magnetic database search using spin wave superposition. The data show a
fundamental speedup over the digital computers without any exponential resource
overhead. We argue that in some cases the classical wave-based approach may
provide the same speedup in database search as quantum computers.
