Scientists worldwide are working on quantum internet to let quantum devices
exchange some information within an environment that harnesses quantum
mechanics’ weird laws. It will use quantum bits or qubits that can be 0 and 1
at the same time.
Even though researchers are working on it now, but the truth is the first
step was taken in the last decade. At that time, two quantum devices were
connected via a physical link.
To create a scalable quantum network, it is essential to pass quantum
information through intermediate nodes. Also, several applications rely on
entangled quantum bits distributed between multiple nodes.
Quantum entanglement offers quantum computers enormous power, and it is the
fundamental resource for sharing quantum information over the future quantum
internet.
By realizing their quantum network in the lab, a team of researchers at
QuTech—a collaboration between Delft University of Technology and TNO—is the
first to have connected two quantum processors through an intermediate node
and established shared entanglement between multiple stand-alone quantum
processors.
Usually, the quantum network consists of three quantum nodes at some
distance within the same building. To prepare these nodes to operate,
scientists invented a novel architecture that enables scaling beyond a
single link.
The middle node (called Bob) has a physical connection to both outer nodes
(called Alice and Charlie), allowing entanglement links with each of these
nodes to be established. Bob is equipped with an additional quantum bit that
can be used as memory, allowing a previously generated quantum link to be
stored while a new link is being established. After establishing the quantum
links Alice-Bob and Bob-Charlie, a set of quantum operations at Bob converts
these links into a quantum link Alice-Charlie. Alternatively, by performing
a different set of quantum operations at Bob, entanglement between all three
nodes is established.
An exciting feature of this quantum network is that it announces the
successful completion of these (intrinsically probabilistic) protocols with
a “flag” signal. Such heralding is crucial for scalability, as, in a future
quantum internet, many of such protocols will need to be concatenated.
Sophie Hermans, another member of the team, said, “Once established, we
could preserve the resulting entangled states, protecting them from noise.
It means that, in principle, we can use these states for quantum key
distribution, a quantum computation, or any other subsequent quantum
protocol.”
This newly established first entanglement-based quantum network offers
scientists a unique testbed for developing and testing quantum internet
hardware, software, and protocols.
Ronald Hanson, who led the research team, said, “Colleagues at QuTech are
already looking into future compatibility with existing data
infrastructures. In due time, the current proof-of-principle approach will
be tested outside the lab on existing telecom fiber—on QuTech’s Quantum
internet Demonstrator, of which the first metropolitan link is scheduled to
be completed in 2022.”
In the future, scientists are looking forward to adding more quantum bits to
their three-node network and on adding higher-level software and hardware
layers.
Pompili said, “Once all the high-level control and interface layers for
running the network have been developed, anybody will be able to write and
run a network application without needing to understand how lasers and
cryostats work. That is the end goal.”
Reference:
“Realization of a multinode quantum network of remote solid-state qubits”
Science (2021). DOI:
10.1126/science.abg1919
Tags:
Physics