TY - JOUR
AB - We combine experimental and theoretical approaches to explore excited rotational states of molecules embedded in helium nanodroplets using CS2 and I2 as examples. Laser-induced nonadiabatic molecular alignment is employed to measure spectral lines for rotational states extending beyond those initially populated at the 0.37 K droplet temperature. We construct a simple quantum-mechanical model, based on a linear rotor coupled to a single-mode bosonic bath, to determine the rotational energy structure in its entirety. The calculated and measured spectral lines are in good agreement. We show that the effect of the surrounding superfluid on molecular rotation can be rationalized by a single quantity, the angular momentum, transferred from the molecule to the droplet.
AU - Cherepanov, Igor
AU - Bighin, Giacomo
AU - Schouder, Constant A.
AU - Chatterley, Adam S.
AU - Albrechtsen, Simon H.
AU - Muñoz, Alberto Viñas
AU - Christiansen, Lars
AU - Stapelfeldt, Henrik
AU - Lemeshko, Mikhail
ID - 10631
IS - 6
JF - Physical Review A
SN - 2469-9926
TI - Excited rotational states of molecules in a superfluid
VL - 104
ER -
TY - JOUR
AB - In the recent years important experimental advances in resonant electro-optic modulators as high-efficiency sources for coherent frequency combs and as devices for quantum information transfer have been realized, where strong optical and microwave mode coupling were achieved. These features suggest electro-optic-based devices as candidates for entangled optical frequency comb sources. In the present work, I study the generation of entangled optical frequency combs in millimeter-sized resonant electro-optic modulators. These devices profit from the experimentally proven advantages such as nearly constant optical free spectral ranges over several gigahertz, and high optical and microwave quality factors. The generation of frequency multiplexed quantum channels with spectral bandwidth in the MHz range for conservative parameter values paves the way towards novel uses in long-distance hybrid quantum networks, quantum key distribution, enhanced optical metrology, and quantum computing.
AU - Rueda Sanchez, Alfredo R
ID - 9242
IS - 2
JF - Physical Review A
SN - 2469-9926
TI - Frequency-multiplexed hybrid optical entangled source based on the Pockels effect
VL - 103
ER -
TY - JOUR
AB - Classical models with complex energy landscapes represent a perspective avenue for the near-term application of quantum simulators. Until now, many theoretical works studied the performance of quantum algorithms for models with a unique ground state. However, when the classical problem is in a so-called clustering phase, the ground state manifold is highly degenerate. As an example, we consider a 3-XORSAT model defined on simple hypergraphs. The degeneracy of classical ground state manifold translates into the emergence of an extensive number of Z2 symmetries, which remain intact even in the presence of a quantum transverse magnetic field. We establish a general duality approach that restricts the quantum problem to a given sector of conserved Z2 charges and use it to study how the outcome of the quantum adiabatic algorithm depends on the hypergraph geometry. We show that the tree hypergraph which corresponds to a classically solvable instance of the 3-XORSAT problem features a constant gap, whereas the closed hypergraph encounters a second-order phase transition with a gap vanishing as a power-law in the problem size. The duality developed in this work provides a practical tool for studies of quantum models with classically degenerate energy manifold and reveals potential connections between glasses and gauge theories.
AU - Medina Ramos, Raimel A
AU - Serbyn, Maksym
ID - 10545
IS - 6
JF - Physical Review A
SN - 2469-9926
TI - Duality approach to quantum annealing of the 3-variable exclusive-or satisfiability problem (3-XORSAT)
VL - 104
ER -