Unbiasing fermionic auxiliary-field quantum Monte Carlo with matrix product state trial wavefunctions
Physical Review Research,
Journal Year:
2025,
Volume and Issue:
7(1)
Published: Jan. 10, 2025
In
this
work,
we
report,
for
the
first
time,
an
implementation
of
fermionic
auxiliary-field
quantum
Monte
Carlo
(AFQMC)
using
matrix
product
state
(MPS)
trial
wavefunctions,
dubbed
MPS-AFQMC.
Calculating
overlaps
between
MPS
and
arbitrary
Slater
determinants
up
to
a
multiplicative
error,
crucial
subroutine
in
MPS-AFQMC,
is
proven
be
#P-hard.
Nonetheless,
tested
several
promising
heuristics
successfully
improving
phaseless
AFQMC
energies.
We
also
proposed
way
evaluate
local
energy
force
bias
evaluations
free
operators.
This
allows
larger
basis
set
calculations
without
significant
overhead.
showcase
utility
our
approach
on
one-
two-dimensional
hydrogen
lattices,
even
when
itself
struggles
obtain
high
accuracy.
Our
work
offers
new
tools
that
can
solve
currently
challenging
electronic
structure
problems
with
future
improvements.
Published
by
American
Physical
Society
2025
Language: Английский
Beyond CCSD(T) Accuracy at Lower Scaling with Auxiliary Field Quantum Monte Carlo
Journal of Chemical Theory and Computation,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 5, 2025
We
introduce
a
black-box
auxiliary
field
quantum
Monte
Carlo
(AFQMC)
approach
to
perform
highly
accurate
electronic
structure
calculations
using
configuration
interaction
singles
and
doubles
(CISD)
trial
states.
This
method
consistently
provides
more
energy
estimates
than
coupled
cluster
with
perturbative
triples
(CCSD(T)),
often
regarded
as
the
gold
standard
in
chemistry.
level
of
precision
is
achieved
at
lower
asymptotic
computational
cost,
scaling
O(N6)
compared
O(N7)
CCSD(T).
provide
numerical
evidence
supporting
these
findings
through
results
for
challenging
main
group
transition
metal-containing
molecules.
Language: Английский
Walking through Hilbert Space with Quantum Computers
Chemical Reviews,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 2, 2025
Computations
of
chemical
systems'
equilibrium
properties
and
nonequilibrium
dynamics
have
been
suspected
being
a
"killer
app"
for
quantum
computers.
This
review
highlights
the
recent
advancements
algorithms
tackling
complex
sampling
tasks
in
key
areas
computational
chemistry:
ground
state,
thermal
state
properties,
calculations.
We
broad
range
algorithms,
from
hybrid
quantum-classical
to
fully
quantum,
focusing
on
traditional
Monte
Carlo
family,
including
Markov
chain
Carlo,
variational
projector
path
integral
etc.
also
cover
other
relevant
techniques
involving
tasks,
such
as
quantum-selected
configuration
interaction,
minimally
entangled
typical
states,
entanglement
forging,
Carlo-flavored
Lindbladian
dynamics.
provide
comprehensive
overview
these
algorithms'
classical
counterparts,
detailing
their
theoretical
frameworks
discussing
potentials
challenges
achieving
advantages.
Language: Английский