document: For any quantum dynamical method, existing or emerging, reliable benchmarks are required to assess their accuracy. A model Hamiltonian exhibiting tunnelling dynamics through a multidimensional asymmetric double well potential has been used as a test by the MP/SOFT [18] and CCS methods [19] mentioned above, and also more recently by a configuration interaction (CI) expansion method [20] and two-layer version of CCS (2L-CCS). [21] The Hamiltonian consists of a 1-dimensional tunnelling mode coupled to an (M−1)-dimensional harmonic bath, hence it is a system-bath problem which bears some similarity to the Caldeira-Leggett model of tunnelling in a dissipative system [22,23]. This Hamiltonian is non-dissipative, however and the harmonic modes all have the same frequency. System-bath models play an important role in physics, being used to describe superconductivity at a Josephson junction in a superconducting quantum interface device (SQUID) [24], for which the Caldeira-Leggett model provides a theoretical basis, and magnetic and conductance phenomena in the spin-bath regime [25].
extractive_keyphrases: a model hamiltonian benchmarks ccs methods ci configuration interaction hamiltonian harmonic modes magnetic and conductance phenomena multidimensional asymmetric double well potential physics quantum dynamical method squid superconducting quantum interface device superconductivity at a josephson junction tunnelling dynamics
abstractive_keyphrases: 1-dimensional tunnelling mode 2l-ccs caldeira-leggett model caldeira-leggett model of tunnelling configuration interaction (ci) expansion method (m−1)-dimensional harmonic bath mp/soft spin-bath regime system-bath models system-bath problem the hamiltonian two-layer version of ccs