Add related libraries

README.md

@@ -25,3 +25,20 @@ Ket is a registered Julia package, so it can be installed by typing
 ```
 
 into the Julia REPL.
+
+## Related libraries
+
+Julia:
+<!--- [BellPolytopes.jl](https://github.com/ZIB-IOL/BellPolytopes.jl)-->
+<!--- [QuantumInformation.jl](https://github.com/iitis/QuantumInformation.jl) (abandoned)-->
+- [QuantumOptics.jl](https://github.com/qojulia/QuantumOptics.jl)
+- [QuantumToolbox.jl](https://github.com/qutip/QuantumToolbox.jl)
+- [Yao.jl](https://github.com/QuantumBFS/Yao.jl)
+
+Python:
+<!--- [qutip](https://github.com/qutip/qutip)-->
+<!--- [qutip-qip](https://github.com/qutip/qutip-qip)-->
+- [toqito](https://github.com/vprusso/toqito)
+
+MATLAB:
+- [QETLAB](https://github.com/nathanieljohnston/QETLAB)