Related papers: Macroscopic quantum tunneling in nanoelectromechan…
Analyzing recent experimental results, we find similar behaviors and a deep analogy between three-junction superconducting qubits and suspended carbon nanotubes. When these different systems are ac-driven near their resonances, the…
The superconducting ground state in many two-dimensional materials can be created or destroyed through quantum phase transitions (QPTs) controlled by non-thermal parameters such as carrier density or magnetic field. While various mechanisms…
A pristine suspended carbon nanotube is a near ideal environment to host long-lived quantum states. For this reason, they have been used as the core element of qubits and to explore numerous condensed matter physics phenomena. One of the…
Coupling the vibrations of an oscillator to electronic transport is a key building block for nanoelectromechanical systems. They describe many nanoscale electrical components such as molecular junctions. Inspired by recent experimental…
We show that by magnetically trapping a superconducting microsphere close to a quantum circuit, it is experimentally feasible to perform ground-state cooling and to prepare quantum superpositions of the center-of-mass motion of the…
We investigate macroscopic dynamical quantum tunneling (MDQT) in the driven Duffing oscillator, charateristic for Josephson junction physics and nanomechanics. Under resonant conditions between stable coexisting states of such systems we…
The strong coupling between electronic transport in a single-level quantum dot and a capacitively coupled nano-mechanical oscillator may lead to a transition towards a mechanically-bistable and blocked-current state. Its observation is at…
We describe a hybrid quantum system composed of a micrometer-size carbon nanotube (CNT) longitudinally coupled to a flux qubit. We demonstrate the usefulness of this device for generating high-fidelity nonclassical states of the CNT via…
Low-temperature characters of superconducting devices yield definite probes for different superconducting phenomena. We study the macroscopic quantum tunneling (MQT) in a Josephson junction, composed of a single-gap superconductor and a…
Quantum criticality is the intriguing possibility offered by the laws of quantum mechanics when the wave function of a many-particle physical system is forced to evolve continuously between two distinct, competing ground states. This…
Macroscopic quantum tunneling (MQT) is a fundamental phenomenon of quantum mechanics related to the actively debated topic of quantum-to-classical transition. The ability to realize MQT affects implementation of qubit-based quantum…
We measure tunneling through a single quantum level in a carbon nanotube quantum dot connected to resistive metal leads. For the electrons tunneling to/from the nanotube, the leads serve as a dissipative environment, which suppresses the…
Symmetry breaking at surfaces and interfaces and the capability to support large strain gradients in nanoscale systems enable new forms of electromechanical coupling. Here we introduce the concept of quantum flexoelectricity, a phenomenon…
We present measurements of tunneling magneto-resistance (TMR) in single-wall carbon nanotubes attached to ferromagnetic contacts in the Coulomb blockade regime. Strong variations of the TMR with gate voltage over a range of four conductance…
In this dissertation, thermal and electrical properties of aligned multiwall carbon nanotubes (MWNTs) prepared by thermal decomposition of hydrocarbons have been experimentally studied. The thesis consists of six chapters. Ch1 is an…
Recent experiments on macroscopic quantum tunneling reveal a non-exponential decay of the number of atoms trapped in a quasibound state behind a potential barrier. Through both experiment and theory, we demonstrate this non-exponential…
We have investigated macroscopic quantum tunneling (MQT) in in-plane high-Tc superconductor Josephson junctions and the influence of the nodal-quasiparticle and the zero energy bound states (ZES) on MQT. We have shown that the presence of…
With an increasing complexity of nanoscopic systems and the modeling thereof, new theoretical tools are needed for a reliable calculation of complex systems with strong electronic correlations. To this end, we propose a new approach based…
We have studied tunneling of electrons into multi-wall carbon nanotubes. Nanotube/electrode interfaces with low transparency as well as nanotube/nanotube junctions created with atomic force microscope manipulation have been used. The…
A nanoelectromechanical weak link composed of a carbon nanotube suspended between two normal electrodes in a gap between two superconducting leads is considered. The nanotube is treated as a movable single-level quantum dot in which the…