Quantum kisses change the color of nothing
Even empty gaps have a colour. Now scientists have shown that quantum
jumps of electrons can change the colour of gaps between nano-sized
balls of gold. The new results, published today in the journal Nature,
set a fundamental quantum limit on how tightly light can be trapped.
The team from the Universities of Cambridge, the Basque Country and Paris hav
e
combined tour de force experiments with advanced theories to show how
light interacts with matter at nanometre sizes. The work shows how they
can literally see quantum mechanics in action in air at room
temperature. Because electrons in a metal move easily, shining light
onto a tiny crack pushes electric charges onto and off each crack face
in turn, at optical frequencies.
The oscillating charge across
the gap produces a 'plasmonic' colour for the ghostly region
in-between, but only when the gap is small enough. Team leader Professor
Jeremy Baumberg from the University of Cambridge Cavendish Laboratory
suggests we think of this like the tension building between a
flirtatious couple staring into each other's eyes. As their faces get
closer the tension mounts, and only a kiss discharges this energy. In
the new experiments, the gap is shrunk below 1nm (1 billionth of a
metre) which strongly reddens the gap colour as the charge builds up.
However because electrons can jump across the gap by quantum
tunnelling, the charge can drain away when the gap is below 0.35nm, seen
as a blue-shifting of the colour. As Baumberg says, "It is as if you
can kiss without quite touching lips."
Read more at: http://phys.org/news/
Quantum kisses change the color of nothing
Even empty gaps have a colour. Now scientists have shown that quantum jumps of electrons can change the colour of gaps between nano-sized balls of gold. The new results, published today in the journal Nature, set a fundamental quantum limit on how tightly light can be trapped.
The team from the Universities of Cambridge, the Basque Country and Paris hav
Even empty gaps have a colour. Now scientists have shown that quantum jumps of electrons can change the colour of gaps between nano-sized balls of gold. The new results, published today in the journal Nature, set a fundamental quantum limit on how tightly light can be trapped.
The team from the Universities of Cambridge, the Basque Country and Paris hav
e
combined tour de force experiments with advanced theories to show how
light interacts with matter at nanometre sizes. The work shows how they
can literally see quantum mechanics in action in air at room
temperature. Because electrons in a metal move easily, shining light
onto a tiny crack pushes electric charges onto and off each crack face
in turn, at optical frequencies.
The oscillating charge across the gap produces a 'plasmonic' colour for the ghostly region in-between, but only when the gap is small enough. Team leader Professor Jeremy Baumberg from the University of Cambridge Cavendish Laboratory suggests we think of this like the tension building between a flirtatious couple staring into each other's eyes. As their faces get closer the tension mounts, and only a kiss discharges this energy. In the new experiments, the gap is shrunk below 1nm (1 billionth of a metre) which strongly reddens the gap colour as the charge builds up.
However because electrons can jump across the gap by quantum tunnelling, the charge can drain away when the gap is below 0.35nm, seen as a blue-shifting of the colour. As Baumberg says, "It is as if you can kiss without quite touching lips."
Read more at: http://phys.org/news/
The oscillating charge across the gap produces a 'plasmonic' colour for the ghostly region in-between, but only when the gap is small enough. Team leader Professor Jeremy Baumberg from the University of Cambridge Cavendish Laboratory suggests we think of this like the tension building between a flirtatious couple staring into each other's eyes. As their faces get closer the tension mounts, and only a kiss discharges this energy. In the new experiments, the gap is shrunk below 1nm (1 billionth of a metre) which strongly reddens the gap colour as the charge builds up.
However because electrons can jump across the gap by quantum tunnelling, the charge can drain away when the gap is below 0.35nm, seen as a blue-shifting of the colour. As Baumberg says, "It is as if you can kiss without quite touching lips."
Read more at: http://phys.org/news/
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