We analyze long-range transport through an ac driven triple quantum dot with one single electron. An effective model is proposed for the analysis of photoassisted cotunnel in order to account for the virtual processes which dominate the long-range transport, which takes place at n-photon resonances between the edge quantum dots. The AC field renormalizes the inter dot hopping, modifying the levels hybridization. It results in a non trivial behavior of the current with the frequency and intensity of the external ac field.

We propose the interaction of two electrons in a triple quantum dot as a minimal system to control long-range superexchange transitions. These are probed by transport spectroscopy. Narrow resonances appear indicating the transfer of charge from one side of the sample to the other with the central one being occupied only virtually. We predict that two different intermediate states establish the two arms of a one-dimensional interferometer. We find configurations where destructive interference of the two superexchange trajectories totally blocks the current through the system. We emphasize the role of spin correlations giving rise to lifetime-enhanced resonances. The complex physics involved in the above mentioned systems can be unraveled by investigating simpler configurations that can be realized experimentally. For that purpose, quantum dot arrays are ideal for their scalability, high degree of tunability, and long coherence times [13]. Coupled quantum dots behave as artificial molecules and their coupling is naturally described by hopping Hamiltonians. These characteristics nominate them for simulations of chemical reactions [14] or lattice models [15][16][17]. The interplay of charge and spin correlations introduces unique transport dynamics as the mesoscopic Kondo effect [18] or Pauli spin blockade [19]. The impressive gate control of few-electron triple quantum dots [20][21][22][23] has succeeded the operation of three-electron exchange-only qubits [24][25][26]. In situations where tunneling to the center dot is energetically forbidden, superexchange is responsible for the indirect coupling of the two outer quantum dots, mediated by virtual transitions through the middle one. Evidences of such transitions have been recently reported in the form of sharp current resonances [27,28] and by real-time charge detection [29]. Thus quantum dots offer not only a way to experimentally control superexchange but also the possibility to explore new phenomena based on long-range interactions [30,31].Here we investigate the minimal system with long-range superexchange interactions affected by charge and spin correlations. It requires three sites and two electrons. In particular, two-particle correlations introduce a mechanism for the quantum interference of superexchange transitions. At the degeneracy of (N L ,N C ,N R ) = (1,1,0) and (0,1,1) states-N l being the number of electrons in quantum dot l-charge

We analyze the equilibration process between two either fermionic or bosonic reservoirs containing ultracold atoms with a fixed total number of particles that are weakly connected via a few-level quantum system. We allow for both the temperatures and particle densities of the reservoirs to evolve in time. Subsequently, linearizing the resulting equations enables us to characterize the equilibration process and its time scales in terms of equilibrium reservoir properties and linear-response transport coefficients. Additionally, we investigate the use of such a device as particle transistor or particle capacitor and analyze its efficiency

We investigate the interplay between long range and direct photo-assisted transport in a triple quantum dot chain where local ac voltages are applied to the outer dots. We propose the phase difference between the two ac voltages as external parameter, which can be easily tuned to manipulate the current characteristics. For gate voltages in phase opposition we find quantum destructive interferences analogous to the interferences in closed loop undriven triple dots. As the voltages oscillate in phase, interferences between multiple paths give rise to dark states. Those totally cancel the current, and could be experimentally resolved.