Bell states in a resonant quantum waveguide network

Abstract

We show that a network of ballistic electron waveguides can generate entangled Bell-like states from separable states when it is resonant. The network we study is grouped into individual qudits ͑d =4͒ made up of pairs of waveguides. Rotation gates in the network produce coherent superpositions of qudit states. A Coulomb gate entangles the qudits. We construct a unitary matrix which characterizes the network dynamics and allows a more systematic study of that dynamics.and9 ͉u͘ A ͉1͘ B + l,10 ͉u͘ A ͉0͘ B + r,11 ͉u͘ A ͉u͘ B + r,12 ͉u͘ A ͉d͘ B + l,13 ͉d͘ A ͉1͘ B + l,14 ͉d͘ A ͉0͘ B + r,15 ͉d͘ A ͉u͘ B + r,16 ͉d͘ A ͉d͘ B . ͑29͒

Electron interference and entanglement in coupled 1D systems with noise

“…In this section, we first describe a two-electron interferom- we adopt a model of Coulomb gate already introduced in Ref. [10]. The Coulomb energy potential between the two particles in the inner channels has been taken proportional to the inverse of the distance D within the interaction window, i.e.…”

“…Recent experiments showed the feasibility of electron interferometers in 1D semiconductor systems, such as quantum wires [6,7] and edge states operating in the integer quantum Hall regime [8,9]. The former, relying on the quantization of conductance in narrow constrictions within two-dimensional electron gases, have been the subject of a number of theoretical [10,11,12,13] and experimental [6,14,15,16] works aimed at investigating their potential applications as quantum logic devices. In particular, the possibility of realizing a universal set of quantum gates by means of coupled quantum wires was proven in Ref.…”

“…Two charge carriers are emitted by the sources S A and S B into two single-particle interferometers, namely A and B. Beyond the one-qubit gates, the system involves a conditional phase gate consisting of a coupling block which correlates, via Coulomb interaction, the qubit states of the electrons propagating in the subsystems A and B. Coulomb interaction between electrons has already been proposed as mechanism to entangle waveguide-based qubits and therefore to implement a two-qubit gate[17,11,10].The coupling block sketched in Fig. 3 consists of a section of length l where the inner waveguides, namely 1 A and 0 B , are brought close to each other in order to "activate" the Coulomb repulsion between the electrons travelling in those channels.…”

EffectiveSmatrix from conductance data in a quantum waveguide

“…We implemented a finite element solution of the Schrödinger equation. 9,11 Calculations were performed on the energy range which allows 5 propagating channels in the right lead for WG ͑a͒ in Fig. 1.…”

Subwavelength Interferometric Control of Absorption in Three-port Acoustic Network

“…On the other hand, complex photonic circuits have been studied and designed for optical signal processing or computing in integrated optics 33,34 . From theoretical perspective, the study of complex multi-port networks is also a vibrant area of research attracting considerable attention in different fields, including plasmonics [35][36][37][38] , quantum transport 39,40 and acoustics [41][42][43][44] .…”