A proposal for using molecular spin qudits as quantum simulators of light–matter interactions

Abstract

We show that molecular spin qudits provide an ideal platform to simulate the quantum dynamics of photon fields strongly interacting with matter. The basic unit of the proposed molecular quantum...

Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla

“…These are characterized by an 8-level nuclear spin coupled to an electronic qubit, particularly promising for quantum computing applications, 25 such as quantum-error correction 33 or quantum simulation. 44 In this respect, the 8 levels of the spin qudit could be used to encode a system characterized by several degrees of freedom, such as a photon or a phonon mode interacting with an atom. 44 In this scheme, the qudit levels m I ¼ 7/2, 5/2, ., À7/2 would represent states with n ¼ 0, 1, ., 7 photons, thus enabling the simulation of the interaction between matter and a quantized eld even in the ultra-strong coupling regime.…”

“…44 In this respect, the 8 levels of the spin qudit could be used to encode a system characterized by several degrees of freedom, such as a photon or a phonon mode interacting with an atom. 44 In this scheme, the qudit levels m I ¼ 7/2, 5/2, ., À7/2 would represent states with n ¼ 0, 1, ., 7 photons, thus enabling the simulation of the interaction between matter and a quantized eld even in the ultra-strong coupling regime. Such a simulation could be implemented by a sequence of pulses resonant with nuclear or electronic spin transitions, along the lines of ref.…”

“…25 Moreover, quantum simulation schemes have recently been put forward, exploiting the qudit multi-level structure to represent bosonic elds. 44 In many cases, the coupling of the qudit with a spin 1/2 ancilla can provide an additional tool, e.g. to detect errors occurring on the qudit, 33 or to simulate photons interacting with matter.…”

“…to detect errors occurring on the qudit, 33 or to simulate photons interacting with matter. 44 The simplest chemical realization of such a platform is provided by a single magnetic-ion complex, embedding a nuclear 32,33,43 spin I coupled by hyperne interaction to an electronic spin doublet. A good candidate should fulll the following requirements: (i) an electronic and nuclear energy level structure yielding well distinguished transitions; (ii) nuclear and electronic coherence times much longer than the time required to manipulate the system; (iii) the capability to coherently control the qudit dynamics, thus implementing the elementary operations which can then be combined into relevant algorithms.…”

“…By removing the strict requirements on the nuclear quadrupole interaction, our approach largely extends the class of electro-nuclear spin systems suitable to implement quantum-error correction, 33 quantum simulation 44 and in general qudit-based algorithms. 25 In particular, vanadium-based complexes, 5,6,10,49 characterized by very long nuclear and electronic coherence but with small nuclear quadrupole coupling, become extremely promising.…”