Research Project: Spin Akımları Kullanarak Elmas-Nv Merkezleri Arasında Kuantum Dolanıklık Etkileşiminin Gösterilmesi
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Contributors
Funders
ID
TB.00545
Authors
Onbaşlı, Mehmet Cengiz
Faculty Member
Publications
Universal skyrmion logic gates and circuits based on antiferromagnetically coupled skyrmions without a topological Hall effect
(Royal Society of Chemistry, 2024) Onbaşlı, Mehmet Cengiz; Yağan, Rawana; Cheghabouri, Arash Mousavi; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
Nanoscale skyrmions are spin-based quasiparticles that are promising for nonvolatile logic applications. However, the presence of the skyrmion Hall effect (SkHE) in ferromagnetic skyrmions limits their performance in logic devices. Here, we present a detailed micromagnetic modeling study on low-energy skyrmion logic gate circuits based on skyrmions in synthetic antiferromagnetically coupled (SAF) metallic ferromagnetic layers to eliminate the SkHE while reducing current requirements. First, we demonstrate the functionalities of the SAF skyrmion logic inverter gate and other Boolean gates such as NOR, OR, AND, and NAND using the inverter gate block and show the improved performance over their ferromagnetic skyrmion gate counterparts. We analyzed the operation and energy consumption at different stages of the SAF skyrmion logic operation and found that the SAF gates can operate at lower current densities. We designed a multiplexer circuit as a test case and obtained a fast response and low Joule heating. The skyrmion motion through the gates is shown to be stable and efficient in different regions, and cascading the gates creates longer linear motion without the unwanted transverse SkHE. Overall, the results indicate the feasibility of antiferromagnetically coupled skyrmions for low-energy logic with improved performance over ferromagnetic skyrmionics.
Continuous-variable polarization mode entanglement in a V-type micromaser
(Elsevier, 2023) Müstecaplıoğlu, Özgür Esat; Mousavitaha, Kowsar Al-Sadat; Faizi, Esfandyar; Department of Physics; Yes; College of Sciences
The micromaser is an archetype experimental setting where a beam of excited two-level atoms is injected into a high-finesse cavity. It has played a pivotal role as a testbed for predictions of quantum optics. We consider a generalized micromaser setting consisting of a high-quality cavity pumped by a beam of three -level atoms. The atoms are assumed to be prepared to carry quantum coherence between their excited state doublet. Our objective is to produce quantum entanglement between the right-handed circular (RHC) and left-handed circular (LHC) polarized photons in the cavity, exploiting the quantum coherence in the pump atoms. For that aim, we derive the generalized micromaser master equation for our system. We find that the dynamics of the micromaser field driven by the pump beam is equivalent to two non-interacting RHC and LHC photonic systems sharing a common non-equilibrium environment. The effect of the shared bath is to mediate an incoherent interaction between the otherwise non-interacting cavity photons, which emerges only if the atoms carry quantum coherence. We take into account cavity losses as a source of quantum decoherence and characterize the quantum entanglement between the LHC and RHC polarized photons in terms of logarithmic negativity, Hillery-Zubairy and spin squeezing criterion, calculated using the dynamical solution of the master equation. We show that, in the same parameter regime, one of the criteria shows entanglement while for the other never detects entanglement. Our results reveal that LHC and RHC polarized photons can be entangled in the transient regime according to the logarithmic negativity criterion.
