A fundamental question in the study of chemical reactions is how reactions proceed at a collision energy close to absolute zero. This question is no longer hypothetical: quantum degenerate gases of atoms and molecules can now be created at temperatures lower than a few tens of nanokelvin. Here we consider the benchmark ultracold reaction between, the most-celebrated ultracold molecule, KRb and K. We map out an accurate ab initio ground-state potential energy surface of the K2Rb complex in full dimensionality and report numerically-exact quantum-mechanical reaction dynamics. The distribution of rotationally resolved rates is shown to be Poissonian. An analysis of the hyperspherical adiabatic potential curves explains this statistical character revealing a chaotic distribution for the short-range collision complex that plays a key role in governing the reaction outcome.

Efficiently entangling pairs of qubits is essential to fully harness the power of quantum computing. Here, we devise an exact protocol that simultaneously entangles arbitrary pairs of qubits on a trapped-ion quantum computer. The protocol requires classical computational resources polynomial in the system size, and very little overhead in the quantum control compared to a single-pair case. We demonstrate an exponential improvement in both classical and quantum resources over the current state of the art. We implement the protocol on a software-defined trapped-ion quantum computer, where we reconfigure the quantum computer architecture on demand. Our protocol may also be extended to a wide variety of other quantum computing platforms.

Reprogrammed metabolism is one of the hallmarks of cancer. The dysregulation of glycolysis in cancer has been heavily studied. However, it remains largely unclear how other metabolic processes are regulated in cancer cells. Here we show that microRNA-182 (miR-182) suppresses pyruvate dehydrogenase (PDH) kinase 4 (PDK4) and promotes lung tumorigenesis. miR-182 is dysregulated and inversely correlated with PDK4 in human lung adenocarcinomas. The miR-182-PDK4 axis regulates lung cancer cell growth by modulating the activity of PDH, the gatekeeping enzyme of pyruvate flux into acetyl-CoA, and subsequently de novo lipogenesis of cancer cells. Suppression of lipogenesis by silencing ATP citrate lyase (ACLY) and fatty acid synthase (FASN) or by chemical inhibitors diminishes the effects of miR-182-PDK4 in tumor growth. Alteration of de novo lipogenesis also affects reactive oxygen species (ROS) production and the downstream JNK signaling pathway. Hence, our work suggests that the miR-182-PDK4 axis is a crucial regulator of cancer cell metabolism and a potential target for antitumor therapy.

Superpositions of rotational states in polar molecules induce strong, long-range dipolar interactions. Here we extend the rotational coherence by nearly one order of magnitude to 8.7(6) ms in a dilute gas of polar 23 Na 40 K molecules in an optical trap. We demonstrate spin-decoupled magic trapping, which cancels first-order and reduces second-order differential light shifts. The latter is achieved with a dc electric field that decouples nuclear spin, rotation, and trapping light field. We observe density-dependent coherence times, which can be explained by dipolar interactions in the bulk gas.Interacting particles with long coherence times are a key ingredient for entanglement generation and quantum engineering. Cold and ultracold polar molecules [1][2][3][4][5][6][7][8][9][10][11] are promising systems for exploring such quantum manybody physics with long-range interactions [12,13] due to their strong and tunable electric dipole moment and long single-particle lifetime [14,15]. The manipulation of their rich internal degrees of freedom has been studied for different molecular species [16][17][18][19]. First observations include ultracold chemistry and collisions [20,21]. Nuclear spin states in the rovibronic ground state further promise exciting prospects for quantum computation due to their extremely long coherence times [22].Rotation is a particularly appealing degree of freedom for molecules because it is directly linked to their dipolar interactions. It can be manipulated by microwave (MW) fields and superpositions of rotational states with opposite parity exhibit an oscillating dipole moment with a magnitude close to the permanent electric dipole moment d 0 . Consequently, using rotating polar molecules has been proposed for quantum computation [23], to emulate exotic spin models [24] or to create topological superfluids [25].In order to make use of the rotational transition dipole in a spatially inhomogeneous optical trap, the coupling of the rotation to the trap field needs to be canceled. To first order this may be achieved by choosing an appropriate angle between the angular momentum of the molecule and the trapping field polarization ε [26] or a special trap light intensity [19] such that the differential polarizability between rotational ground and excited states is canceled. The trap is then referred to as "magic". Coherence times of about 1 ms have been achieved in bulk gases of polar molecules using these techniques [19,27]. However, this is much shorter than the dipolar interaction time, preventing observation of many-body spin dynamics.The coherence time in such a magic trap is limited by the intensity dependence of the molecular polarizabil-ity, which originates from the coupling between rotation, nuclear spins, and the trapping light field. It has been suggested to apply large magnetic [28] or electric fields [29] to reduce these couplings and thus simplify the polarizabilities of the involved states.In this work, we realize a spin-decoupled magic trap, i.e. a magic polarization angle trap wit...