Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear
  spin qudit   We explore how to encode more than a qubit in vanadyl porphyrin molecules
hosting a electronic spin 1/2 coupled to a nuclear spin 7/2. The spin
Hamiltonian and its parameters, as well as the spin dynamics, have been
determined via a combination of electron paramagnetic resonance, heat capacity,
magnetization and on-chip magnetic spectroscopy experiments performed on single
crystals. We find low temperature spin coherence times of micro-seconds and
spin relaxation times longer than a second. For sufficiently strong magnetic
fields (B larger than 0.1 T, corresponding to resonance frequencies of 9 to 10
GHz) these properties make vanadyl porphyrin molecules suitable qubit
realizations. The presence of multiple equispaced nuclear spin levels then
merely provides 8 alternatives to define the 0 and 1 basis states. For lower
magnetic fields (below 0.1 T), and lower frequencies (smaller than 2 GHz), we
find spectroscopic signatures of a sizeable electronuclear entanglement. This
effect generates a larger set of allowed transitions between different
electronuclear spin states and removes their degeneracies. Under these
conditions, we show that each molecule fulfills the conditions to act as a
universal 4-qubit processor or, equivalently, as a d = 16 qudit. These findings
widen the catalogue of chemically designed systems able to implement
non-trivial quantum functionalities, such as quantum simulations and,
especially, quantum error correction at the molecular level.

14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex