Insights into the value of the market for cocaine, heroin and methamphetamine in South Africa

The illicit drug trade generates billions of dollars and sustains transnational criminal organisations. Drug markets can destabilise governance and undermine development. Data indicate increasing drug use in South Africa. However, information on the size and value of the drug market is limited. This is the first study to estimate the market value of cocaine, heroin and methamphetamine in South Africa. People who use drugs were meaningfully involved in all aspects of implementation. We used focus group discussions, ethnographic mapping, brief interviews, and the Delphi method to estimate the number of users, volumes consumed, and price for each drug in South Africa in 2020. Nationally, we estimated there to be: 400,000 people who use heroin (probability range (PR) 215,000–425,000) consuming 146.00 tonnes (PR 78.48–155.13) with a value of US$1,898.00 million (PR US$1,020.18–US$2,016.63); 350,000 people who use cocaine (PR 250,000–475,000) consuming 18.77 tonnes (PR 13.41–25.47) with a market value of US$1,219.86 million (PR 871.33–1,655.52) and 290,000 people who use methamphetamine (PR 225,000–365,000) consuming 60.19 tonnes (PR 6.58–10.68) and a market value of US$782.51 million (PR 607.12–984.88). The combined value was calculated at US$3.5 billion. Findings can be used to stimulate engagement to reform drug policy and approaches to mitigate the impact of the illicit drug trade. Additional studies that include people who use drugs in research design and implementation are needed to improve our understanding of drug markets

Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transitions. To take advantage of this accuracy an ultracold helium sample is needed. For measurements of the triplet spectrum a magneto-optical trap (MOT) can be used to cool and trap metastable 2^3S state atoms. We analyze schemes for measuring the two-photon $2^3S \to 4^3S$ interval, and for resonant two-photon excitation to high Rydberg states, $2^3S \to 3^3P \to n^3S,D$. We also analyze experiments on the singlet-state spectrum. To accomplish this we propose schemes for producing and trapping ultracold helium in the 1^1S or 2^1S state via intercombination transitions. A particularly intriguing scenario is the possibility of measuring the $1^1S \to 2^1S$ transition with extremely high accuracy by use of two-photon excitation in a magic wavelength trap that operates identically for both states. We predict a ``triple magic wavelength'' at 412 nm that could facilitate numerous experiments on trapped helium atoms, because here the polarizabilities of the 1^1S, 2^1S and 2^3S states are all similar, small, and positive.Comment: Shortened slightly and reformatted for Eur. Phys. J.

Entanglement of Atomic Qubits using an Optical Frequency Comb

We demonstrate the use of an optical frequency comb to coherently control and entangle atomic qubits. A train of off-resonant ultrafast laser pulses is used to efficiently and coherently transfer population between electronic and vibrational states of trapped atomic ions and implement an entangling quantum logic gate with high fidelity. This technique can be extended to the high field regime where operations can be performed faster than the trap frequency. This general approach can be applied to more complex quantum systems, such as large collections of interacting atoms or molecules.Comment: 4 pages, 5 figure

A Modified Approach to Single-Spin Detection Using Magnetic Resonance Force Microscopy

The magnetic moment of a single spin interacting with a cantilever in magnetic resonance force microscopy (MRFM) experiences quantum jumps in orientation rather than smooth oscillations. These jumps cannot be detected by a conventional MRFM based on observation of driven resonant oscillations of a cantilever. In this paper, we propose a method which will allow detection of the magnetic signal from a single spin using a modification of a conventional MRFM. We estimate the opportunity to detect the magnetic signal from a single proton.Comment: 4 pages LaTex, 4 figures in GIF forma

Velocity-selective direct frequency-comb spectroscopy of atomic vapors

We present an experimental and theoretical investigation of two-photon direct frequency-comb spectroscopy performed through velocity-selective excitation. In particular, we explore the effect of repetition rate on the $\textrm{5S}_{1/2}\rightarrow \textrm{5D}_{3/2, 5/2}$ two-photon transitions excited in a rubidium atomic vapor cell. The transitions occur via step-wise excitation through the $\textrm{5P}_{1/2, 3/2}$ states by use of the direct output of an optical frequency comb. Experiments were performed with two different frequency combs, one with a repetition rate of $\approx 925$ MHz and one with a repetition rate of $\approx 250$ MHz. The experimental spectra are compared to each other and to a theoretical model.Comment: 10 pages, 7 figure