Toward scalable information processing with ultracold polar molecules in an electric field: A numerical investigation

Abstract

We numerically investigate the possibilities of driving quantum algorithms with laser pulses in a register of ultracold NaCs polar molecules in a static electric field. We focus on the possibilities of performing scalable logical operations by considering circuits that involve intermolecular gates (implemented on adjacent interacting molecules) to enable the transfer of information from one molecule to another during conditional laser-driven population inversions. We study the implementation of an arithmetic operation (the addition of 0 or 1 on a binary digit and a carry in) which requires population inversions only and the Deutsch-Jozsa algorithm which requires a control of the phases. Under typical experimental conditions, our simulations show that high-fidelity logical operations involving several qubits can be performed in a time scale of a few hundreds of microseconds, opening promising perspectives for the manipulation of a large number of qubits in these systems.

Quantum gates in hyperfine levels of ultracold alkali dimers by revisiting constrained-phase optimal control design

“…However, realizing intramolecular gates is a first step and the dipole-dipole interaction could be used to drive intramolecular gates. 41,[44][45][46]54 The coupling with the translational motion in the trap could also be an interesting perspective.…”

“…Ultracold polar molecules which can interact via dipole-dipole interaction are particularly interesting to create entanglement between neighboring molecules and to open the way toward qubit networks. [41][42][43][44][45][46][47][48] Alkali dimers also possess a rich spin structure because both nuclei have a nonzero spin. The spin interactions and the coupling with the overall rotation lead to hyperfine levels which can be further manipulated in magnetic or electric fields.…”

“…It seems intuitive to use the same quantity but it is not always the case in many previous applications. 33,38,44,48,54,55 It has been discussed early that realizing a gate transformation by an optimal field requires a careful choice of the performance measure. 56,57 The average transition probability for each computational basis state is not sufficient because the laser pulse is not able to drive any superposed state as it must do.…”

Luminorefrigeration of NaCs

“…There is significant current interest in acquiring a collection of rovibrational ground state molecules because it is the necessary starting point for a sample that is stable against collisions. These molecules may be used in the creation of dipolar crystals [10,11], quantum computation schemes [12], and quantum chemistry investigations [13].…”

Simulation of the elementary evolution operator with the motional states of an ion in an anharmonic trap

“…As predicted by Feynman, 3 quantum computers could be used as quantum simulators to solve stationary [4][5][6][7][8][9] or non stationary 10-13 quantum problems by simulating them with a controllable experimental setup which allows one to reproduce the dynamics of a given Hamiltonian. Several physical supports have been proposed to encode qubits: 14 photons, 15 spin states using nuclear magnetic resonance (NMR) technology, 16 quantum dots, 17 atoms, 18 molecular rovibrational levels of polyatomic or diatomic molecules, ultracold polar molecules, [48][49][50][51][52][53][54][55][56][57] or a juxtaposition of different types of systems. 58 In the current work, we focus on trapped ions [59][60][61][62][63][64] which remain one of the most attractive candidates due to the long coherence time scales and the possibility of exploiting the strong Coulomb interaction.…”