Despite their popularity in the science fiction genre, there is much to be
learned about black holes, the mysterious regions in space once thought to be
absent of light. In a paper published in the August 20 issue of Physical Review
Letters, the flagship journal of the American Physical Society, Dartmouth
researchers propose a new way of creating a reproduction black hole in the laboratory
on a much-tinier scale than their celestial counterparts.
The new method to create a tiny quantum sized black hole would allow researchers
to better understand what physicist Stephen Hawking proposed more than 35 years
ago: black holes are not totally void of activity; they emit photons, which
is now known as Hawking radiation.
"Hawking famously showed that black holes radiate energy according to
a thermal spectrum," said Paul Nation, an author on the paper and a graduate
student at Dartmouth. "His calculations relied on assumptions about the
physics of ultra-high energies and quantum gravity. Because we can't yet take
measurements from real black holes, we need a way to recreate this phenomenon
in the lab in order to study it, to validate it."
In this paper, the researchers show that a magnetic field-pulsed microwave
transmission line containing an array of superconducting quantum interference
devices, or SQUIDs, not only reproduces physics analogous to that of a radiating
black hole, but does so in a system where the high energy and quantum mechanical
properties are well understood and can be directly controlled in the laboratory.
The paper states, "Thus, in principle, this setup enables the exploration
of analogue quantum gravitational effects."
"We can also manipulate the strength of the applied magnetic field so
that the SQUID array can be used to probe black hole radiation beyond what was
considered by Hawking," said Miles Blencowe, another author on the paper
and a professor of physics and astronomy at Dartmouth.
This is not the first proposed imitation black hole, says Nation. Other proposed
analogue schemes have considered using supersonic fluid flows, ultracold bose-einstein
condensates and nonlinear fiber optic cables. However, the predicted Hawking
radiation in these schemes is incredibly weak or otherwise masked by commonplace
radiation due to unavoidable heating of the device, making the Hawking radiation
very difficult to detect. "In addition to being able to study analogue
quantum gravity effects, the new, SQUID-based proposal may be a more straightforward
method to detect the Hawking radiation," says Blencowe.
In addition to Nation and Blencowe, other authors on the paper include Alexander
Rimberg at Dartmouth and Eyal Buks at Technion in Haifa, Israel.
Posted August 21st, 2009
