arXiv (Cornell University),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Jan. 1, 2023
The
decoherence
effect
caused
by
the
coupling
between
system
and
environment
undoubtedly
leads
to
errors
in
efficient
implementations
of
two
(or
three)
qubit
logical
gates
quantum
information
processing.
Fortunately,
decoherence-free
subspace
(DFS)
introduced
can
effectively
decrease
influence
effect.
In
this
paper,
we
propose
some
schemes
for
setting
up
a
family
control
gates,
including
controlled-NOT
(CNOT),
Toffoli,
Fredkin
or
three
qubits
means
cross-Kerr
nonlinearities
DFS.
These
require
neither
complicated
computational
circuits
nor
auxiliary
photons
entangled
states).
success
probabilities
are
approximate
1
performing
corresponding
classical
feed-forward
operations
based
on
different
measuring
results
X-homodyne
detectors,
their
fidelities
robust
against
photon
loss
with
current
technology.
proposed
rely
only
simple
linear-optics
elements,
available
single-qubit
operations,
mature
measurement
methods,
making
our
be
feasible
practical
applications.
Optics Letters,
Journal Year:
2024,
Volume and Issue:
49(5), P. 1229 - 1229
Published: Feb. 7, 2024
High-dimensional
quantum
systems
expand
channel
capacity
and
information
storage
space.
By
implementing
high-dimensional
logic
gates,
the
speed
of
computing
can
be
practically
enhanced.
We
propose
a
deterministic
4
×
4-dimensional
controlled-not
(CNOT)
gate
for
hybrid
system
without
ancillary
qudits
required,
where
spatial
polarization
states
single
photon
serve
as
control
qudit
four
dimensions,
whereas
two
electron-spin
in
nitrogen-vacancy
(NV)
centers
act
four-dimensional
target
qudit.
As
are
easily
operated
employing
simple
optical
elements
available
storage,
CNOT
works
way,
it
flexibly
extended
to
n
-dimensional
(
>
4)
gates
other
or
different
photonic
degrees
freedoms.
The
efficiency
fidelity
analyzed
aligning
with
current
technological
capabilities,
finding
that
they
have
satisfactory
performances.
Quantum,
Journal Year:
2024,
Volume and Issue:
8, P. 1342 - 1342
Published: May 13, 2024
The
decoherence
effect
caused
by
the
coupling
between
system
and
environment
undoubtedly
leads
to
errors
in
efficient
implementations
of
two
(or
three)
qubit
logical
gates
quantum
information
processing.
Fortunately,
decoherence-free
subspace
(DFS)
introduced
can
effectively
decrease
influence
effect.
In
this
paper,
we
propose
some
schemes
for
setting
up
a
family
control
gates,
including
controlled-NOT
(CNOT),
Toffoli,
Fredkin
or
three
qubits
means
cross-Kerr
nonlinearities
DFS.
These
require
neither
complicated
computational
circuits
nor
auxiliary
photons
entangled
states).
success
probabilities
are
approximate
1
performing
corresponding
classical
feed-forward
operations
based
on
different
measuring
results
X-homodyne
detectors,
their
fidelities
robust
against
photon
loss
with
current
technology.
proposed
rely
only
simple
linear-optics
elements,
available
single-qubit
operations,
mature
measurement
methods,
making
our
be
feasible
practical
applications.
Optics Letters,
Journal Year:
2025,
Volume and Issue:
50(4), P. 1113 - 1113
Published: Jan. 7, 2025
High-dimensional
quantum
gates
not
only
extend
the
existing
computing
framework
but
also
serve
as
a
vital
component
in
range
of
technologies.
In
study,
4
×
4-dimensional
controlled-NOT
(CNOT)
gate
is
presented
based
on
assistance
weak
cross-Kerr
medium,
utilizing
two
degrees
freedom
(DoFs)
with
photons.
Specifically,
control
qudits
are
encoded
photonic
polarization
DoF,
while
target
path
DoF
Notably,
circuit
constructed
using
times
Kerr
outperforming
previous
design
that
required
six
times,
which
simplifies
entire
circuits.
Furthermore,
fidelity
and
success
probability
proposed
protocol
near
1
when
influence
factors
take
appropriate
value.
Optics Express,
Journal Year:
2024,
Volume and Issue:
32(18), P. 31633 - 31633
Published: Aug. 9, 2024
Quantum
computing
in
high-dimensional
spaces
holds
promise
for
a
plethora
of
applications,
i.e.,
handling
more
intricate
information
and
executing
wider
quantum
operations,
complex
technologies
(QITs).
In
the
paper,
we
set
up
an
error-heralded,
resource-saving,
circuit-simplified,
4×4-dimensional
controlled-not
(CNOT)
gate,
where
polarized
spatial
state
flying
photon
(i.e.,
control
qudit)
can
effectively
collective
spin
wave
two
atomic
ensembles
target
double-sided
cavities.
Moreover,
through
meticulous
analysis,
feasibility
gate
using
existing
technology
boasts
exceptional
performance
including
near-unity
fidelity
high
efficiency
exceeding
0.95,
principle,
as
undesired
performances
originated
from
little
side
leakage
finite
coupling
strength,
imperfect
atom-ensemble-cavity
interactions
are
heralded
by
single-photon
detectors.
Besides,
auxiliary
photons
or
unnecessary.
Therefore,
our
protocol
stands
out
its
simplicity,
efficient
resource
utilization,
real-time
error
prediction,
contributing
significantly
to
efficacy
QIT
charting
promising
path
towards
realization
endowed
with
heightened
capabilities.
Scientific Reports,
Journal Year:
2025,
Volume and Issue:
15(1)
Published: Jan. 20, 2025
As
the
hyperentanglement
of
photon
systems
holds
lots
remarkable
applications
for
enhancing
channel
capacity
with
less
quantum
resource,
interconversion
various
hyperentangled
states
warrants
in-depth
investigation
and
becomes
a
vital
work
information
technologies.
Here
we
realize
completely
mutual
conversions
between
spatial-polarization
Knill-Laflamme-Milburn
state
W
three-photon
systems,
resorting
to
hyperparallel
control
gates
practical
nonlinear
interaction
nitrogen-vacancy
centers
coupled
whispering-gallery-mode
microresonators.
The
gates,
i.e.,
controlled-not
controlled-swap
are
fundamental
prerequisites
realizing
interconversions
two
in
deterministic
way.
fidelities
these
conversion
processes
robust
their
efficiencies
also
high
due
fewer
interactions
errors
heralded
by
response
detectors,
which
intensify
comprehending
properties
hyperentanglement.
Quantum,
Journal Year:
2025,
Volume and Issue:
9, P. 1702 - 1702
Published: April 9, 2025
Entanglement
purification
and
distillation
protocols
are
essential
for
harnessing
the
full
potential
of
quantum
communication
technologies.
Multiple
strategies
have
been
proposed
to
approach
optimize
such
protocols,
most
however
restricted
Clifford
operations.
In
this
paper,
we
introduce
a
superposed
entanglement
design
strategy,
leveraging
coherent
superpositions
roles
entangled
states
enhance
efficiency,
defining
new
family
non-Clifford
protocols.
We
demonstrate
how
can
be
hierarchically
integrated
with
existing
strategies,
consistently
improving
performance.
Physical review. A/Physical review, A,
Journal Year:
2024,
Volume and Issue:
109(6)
Published: June 17, 2024
In
this
paper,
we
propose
a
one-step
scheme
for
implementing
the
nonadiabatic
holonomic
swap
gate
with
Rydberg
atoms.
By
applying
invariant-based
reverse
engineering
to
design
effective
Hamiltonian
of
system,
suitable
evolution
path
quantum
computation
is
found.
addition,
systematic-error-sensitivity
nullified
optimal
control
method
considered
in
parameter
selections,
so
that
insensitive
systematic
error
pulses.
We
also
estimate
effects
random
noise,
initial
phase
pulses,
Doppler
shift,
and
decoherence
on
scheme.
The
numerical
results
show
exhibits
fairly
good
performance
against
these
negative
factors.
Finally,
generalize
realize
non-Clifford
gates.
Therefore,
can
provide
feasible
framework
high-fidelity
robust
gates
Advanced Quantum Technologies,
Journal Year:
2024,
Volume and Issue:
7(7)
Published: April 19, 2024
Abstract
Quantum
circuits
of
a
general
quantum
gate
acting
on
multiple
‐level
systems
play
prominent
role
in
multi‐valued
computation.
A
recursive
Cartan
decomposition
semi‐simple
unitary
Lie
group
(arbitrary
‐qutrit
gate)
is
first
proposed
with
rigorous
proof,
which
completely
decomposes
an
into
local
and
non‐local
operations.
On
this
basis,
explicit
circuit
designed
for
implementing
arbitrary
two‐qutrit
gates,
the
cost
construction
21
generalized
controlled
(GCX)
increment
(CINC)
gates
less
than
earlier
best
result
26
GGXs.
Furthermore,
program
extended
to
system,
generic
contained
GGXs
CINCs
presented.
Such
asymptotically
optimal
structure
known
so
far
its
strength
becomes
more
remarkable
as
increases,
example,
when
,
saves
7146
GCXs
compared
previous
result.
In
addition,
concrete
expressions
given
each
operation
instead
only
diagrams.
Advanced Quantum Technologies,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 14, 2025
Abstract
Quantum
logic
gate
forms
the
cornerstone
of
quantum
computing.
Here,
two
error‐detected,
circuit‐compact,
and
fidelity‐robust
SWAP
(SWAP)
()
gates
are
set
for
quantum‐dot
(QD)
spins
with
aid
scattering
property
photon
off
QD
fixed
in
double‐sided
microcavity.
For
an
ideal
single‐photon
scattering,
efficiencies
fidelities
both
can,
principle,
be
close
to
unity.
Otherwise,
being
directed
against
a
nonideal
error‐detected
units
make
their
near
perfect
at
expense
slight
reductions
efficiencies.
Moreover,
work
way
may
experimentally
feasible
current
technique
on
regulating
QD‐cavity
system.
Further,
additional
spin
qubits
not
required,
thereby
reducing
resource
usages
error
rates.
