<s>
Quantum	B-Device
volume	I-Device
is	O
a	O
metric	O
that	O
measures	O
the	O
capabilities	O
and	O
error	O
rates	O
of	O
a	O
quantum	B-Architecture
computer	I-Architecture
.	O
</s>
<s>
It	O
expresses	O
the	O
maximum	O
size	O
of	O
square	O
quantum	B-Application
circuits	I-Application
that	O
can	O
be	O
implemented	O
successfully	O
by	O
the	O
computer	O
.	O
</s>
<s>
The	O
form	O
of	O
the	O
circuits	O
is	O
independent	O
from	O
the	O
quantum	B-Architecture
computer	I-Architecture
architecture	O
,	O
but	O
compiler	O
can	O
transform	O
and	O
optimize	O
it	O
to	O
take	O
advantage	O
of	O
the	O
computer	O
's	O
features	O
.	O
</s>
<s>
Thus	O
,	O
quantum	B-Device
volumes	I-Device
for	O
different	O
architectures	O
can	O
be	O
compared	O
.	O
</s>
<s>
The	O
current	O
world	O
record	O
for	O
highest	O
quantum	B-Device
volume	I-Device
as	O
of	O
February	O
2023	O
is	O
32,768	O
(	O
215	O
)	O
,	O
accomplished	O
by	O
Quantinuum	O
's	O
H1	O
Ion	O
trap	O
quantum	B-Architecture
computer	I-Architecture
.	O
</s>
<s>
Quantum	B-Architecture
computers	I-Architecture
are	O
difficult	O
to	O
compare	O
.	O
</s>
<s>
Quantum	B-Device
volume	I-Device
is	O
a	O
single	O
number	O
designed	O
to	O
show	O
all	O
around	O
performance	O
.	O
</s>
<s>
It	O
is	O
a	O
measurement	O
and	O
not	O
a	O
calculation	O
,	O
and	O
takes	O
into	O
account	O
several	O
features	O
of	O
a	O
quantum	B-Architecture
computer	I-Architecture
,	O
starting	O
with	O
its	O
number	O
of	O
qubits	O
—	O
other	O
measures	O
used	O
are	O
gate	O
and	O
measurement	O
errors	O
,	O
crosstalk	O
and	O
connectivity	O
.	O
</s>
<s>
IBM	O
defined	O
its	O
Quantum	B-Device
Volume	I-Device
metric	O
because	O
a	O
classical	O
computer	O
's	O
transistor	O
count	O
and	O
a	O
quantum	B-Architecture
computer	I-Architecture
's	O
quantum	O
bit	O
count	O
are	O
n't	O
the	O
same	O
.	O
</s>
<s>
Generally	O
,	O
the	O
larger	O
the	O
quantum	B-Device
volume	I-Device
,	O
the	O
more	O
complex	O
the	O
problems	O
a	O
quantum	B-Architecture
computer	I-Architecture
can	O
solve	O
.	O
</s>
<s>
Alternative	O
benchmarks	O
,	O
such	O
as	O
Cross-entropy	B-Device
benchmarking	I-Device
and	O
IonQ	O
's	O
Algorithmic	O
Qubits	O
,	O
have	O
also	O
been	O
proposed	O
.	O
</s>
<s>
The	O
quantum	B-Device
volume	I-Device
of	O
a	O
quantum	B-Architecture
computer	I-Architecture
was	O
originally	O
defined	O
in	O
2018	O
by	O
Nikolaj	O
Moll	O
et	O
al	O
.	O
</s>
<s>
So	O
with	O
these	O
definitions	O
,	O
as	O
soon	O
as	O
,	O
the	O
quantum	B-Device
volume	I-Device
goes	O
down	O
if	O
more	O
qubits	O
are	O
added	O
.	O
</s>
<s>
give	O
a	O
refined	O
definition	O
of	O
quantum	B-Device
volume	I-Device
.	O
</s>
<s>
In	O
2019	O
,	O
IBM	O
's	O
researchers	O
modified	O
the	O
quantum	B-Device
volume	I-Device
definition	O
to	O
be	O
an	O
exponential	O
of	O
the	O
circuit	O
size	O
,	O
stating	O
that	O
it	O
corresponds	O
to	O
the	O
complexity	O
of	O
simulating	O
the	O
circuit	O
on	O
a	O
classical	O
computer	O
:	O
</s>
