Quantum Computing Transforming Computational Chemistry
Key Points
- Classical computational chemistry relies on software packages (e.g., Gaussian, PSI4) that use basis sets and solve the Schrödinger equation with approximations like Born‑Oppenheimer and Hartree‑Fock to obtain properties such as ground‑state energies.
- These classical methods work well for small molecules but their accuracy and computational cost degrade rapidly as molecular complexity grows, leading to exponential scaling beyond Hartree‑Fock.
- To manage the heavy workload, traditional packages often exploit GPUs and high‑performance computing resources, yet they remain limited by the inherent inefficiency of classical algorithms for large quantum systems.
- Quantum computing promises to overcome these limitations by directly tackling the quantum nature of chemical problems, potentially delivering more accurate energy calculations without the exponential scaling bottleneck.
- The speaker, a software developer passionate about chemistry, highlights the growing interest in leveraging quantum‑computing advantages to improve computational chemistry workflows.
Full Transcript
# Quantum Computing Transforming Computational Chemistry **Source:** [https://www.youtube.com/watch?v=8VnZo8wVMm8](https://www.youtube.com/watch?v=8VnZo8wVMm8) **Duration:** 00:07:56 ## Summary - Classical computational chemistry relies on software packages (e.g., Gaussian, PSI4) that use basis sets and solve the Schrödinger equation with approximations like Born‑Oppenheimer and Hartree‑Fock to obtain properties such as ground‑state energies. - These classical methods work well for small molecules but their accuracy and computational cost degrade rapidly as molecular complexity grows, leading to exponential scaling beyond Hartree‑Fock. - To manage the heavy workload, traditional packages often exploit GPUs and high‑performance computing resources, yet they remain limited by the inherent inefficiency of classical algorithms for large quantum systems. - Quantum computing promises to overcome these limitations by directly tackling the quantum nature of chemical problems, potentially delivering more accurate energy calculations without the exponential scaling bottleneck. - The speaker, a software developer passionate about chemistry, highlights the growing interest in leveraging quantum‑computing advantages to improve computational chemistry workflows. ## Sections - [00:00:00](https://www.youtube.com/watch?v=8VnZo8wVMm8&t=0s) **Quantum Computing for Chemical Simulations** - The speaker introduces quantum computing’s potential to enhance computational chemistry, contrasting it with classical tools like Gaussian and PSI‑4, and explains how molecular data and basis sets are used to compute properties such as ground‑state energies, illustrated with water. ## Full Transcript
today we're going to talk about Quantum
Computing applications in chemistry
for many years computational chemists
have been using classical computational
methods to attempt to solve chemistry
problems my background is in software
development but I'm particularly
passionate about the applications of
software within chemistry and the
particular advantages that Quantum
Computing has the potential to bring
many computational chemists will use a
popular software packages such as
gaussian
pie SCF
and PSI 4.
these plus many others all of these
different packages provide a suite of
tools to enable computational chemists
to do research into various different
types of chemistry problems and they all
use particular sets of of data to be
able to do this work and some of the
important data points can include
information about a molecules ground
state energy
excited state energy
as well as potential energy surfaces
um and and many more
but how do we actually
calculate this information for a given
molecule
let's take
um H2O for example
so in order to calculate the ground
state energy of water from a classical
perspective first we're going to need
some information about the molecule
itself we want to know the atoms that
are involved as well as maybe some
different coordinates in space
um and as well as this we're also going
to take a set of functions
known as a basis set
which you can think of as essentially a
mathematical representation of the
different orbitals within the H2O
molecule
so in order to and then we take this
information and what we're going to do
is we're going to plug it into a
Schrodinger equation
uh Schrodinger equation is a very
important equation within chemistry and
Quantum uh quantum mechanics generally
and it defines uh the quantum system
itself and this value e here represents
the energy of our Quantum system in this
case our Quantum system is the H2O
molecule so if we minimize this value of
E
we can get the ground state energy
so how do we actually go about finding
this minimum value of e well there are a
few different things we can do but
firstly what we're wanting to do is make
some assumptions to simplify the problem
of it we can use the born Oppenheimer
approximation as well as the Heart Tree
approximation
and these assumptions essentially make
it easier to compute solutions to this
equation and once we've done that our
output will be a approximation of that
ground state energy
um so so far everything we've done up
till this point
um we can do classically with classical
computers
um however there are a few problems with
this the first one being that
um the accuracy of this value will
decrease as the complexity of our
Quantum system increases
um as well as this if we want to do any
further processing Beyond Heart Tree fog
this becomes exponentially
um more uh difficult and computationally
very expensive very quickly and this is
why software packages like the ones I
mentioned before will often leverage
gpus and high performance computers in
order to try to solve this equation for
more complex molecules
but quantum computers have the potential
to simulate these more complex molecules
more efficiently and to a higher degree
of accuracy Than Just A Heart Tree fog
uh processing and this is because
quantum computers process information in
a fundamentally uh different way than
classical computers do
um so let's go back to our Schrodinger
equation for a minute we can essentially
map this equation onto qubits onto
Quantum bits and we can also incorporate
some of these approximations as well
so we can represent this in Quantum
circuit form
and because we've done this now we can
leverage
um key uh Quantum phenomena such as
superposition
and entanglement
then if we're using kiskit runtime we
can take this Quantum circuit and use it
together with an estimator primitive
as well as an optimizer
and we can take all of that
and plug it into
a variational Quantum eigensolver
algorithm this is a very important
Quantum Computing algorithm that enables
us to calculate eigen eigenvalues
efficiently
um
so if we're and if we're using uh
Primitives these are unique to IBM's
kiss kit runtime they are predefined
programs uh that help users to optimize
their workloads and execute them
efficiently on Quantum systems the
estimator primitive in particular makes
it easier to extract solutions from this
circuit and also give us incredibly
fine-grained control over the system
hardware and the optimization routine so
we can generate the best results
possible
um so once we've done all of that we
will get an output which is again an
approximation of the ground state energy
for our H2O molecule
um but this uh value that we've
calculated here is often more precise
than just doing Heart Tree fog uh
calculations alone and it doesn't
consume compute resources as fast
and this is why
um Quantum Computing researchers
particularly in the field of chemistry
are incredibly excited about the
potential for quantum computers to have
a real impact on the chemistry industry
specifically and with open source tools
like uh kids kit runtime and kiss kit
nature anyone can get started
experimenting with this today and we'll
leave some links in the description uh
for you to get going with that thank you
very much I hope you enjoyed this video
remember to like subscribe leave any
questions that you have in the comments
and remember to check out our other
Quantum videos on this channel