adds README

README.md

@@ -1 +1,22 @@
 # Modeling for Nitrogen-Vacancy Centers in Diamond
+
+Modeling for single NV centers in diamond.
+
+Construct ground state Hamiltonian of NV-negative centers, including
+fine structure, hyperfine structure, nuclear quadrupole,
+and external magnetic field terms.
+
+Includes transformation from lab frame to rotating frame.
+
+Includes tools for plotting eigenvalues, plotting states on the Bloch
+sphere (one must choose the two physical spin states to be
+  represented), and representing states as linear combination of
+  basis states.
+
+
+
+# Demos
+
+1. [Visualizing Spin 1 systems on the Bloch sphere](notebooks/Visualize_spin1_on_bloch_sphere.ipynb)
+2. [NV negative simple fine structure term only, and Bloch sphere](notebooks/NVNegZFS.ipynb)
+3. [NV negative with static and applied MW fields for spin control](notebooks/NVNeg_full_H_Zeeman_splitting.ipynb)

src/nvmodels/hamiltonians/nvnegative.py

@@ -94,7 +94,7 @@ def static_mag_field_hamiltonian(self, B: list[float]=[0,0,0],
           gamma_e B dot S
 
         where gamma_e is the electron gyromagnetic ratio, B is in Tesla,
-        and S is the spin-1 spin vector (and the sign is + because e change is -1)
+        and S is the spin-1 spin vector (and the sign is + because e charge is -1)
 
         If include_nucleus is True, will also apply B field to
         nitrogen. However, the amplitude of this effect is 10,000x smaller
@@ -106,7 +106,7 @@ def static_mag_field_hamiltonian(self, B: list[float]=[0,0,0],
         and I is the spin vector operator for 14N (s = 1) or 15N (s = 1/2).
 
         """
-        # -gamma_e * B dot S
+        # gamma_e * B dot S
         h = B[0] * qt.spin_Jx(1)
         h += B[1] * qt.spin_Jy(1)
         h += B[2] * qt.spin_Jz(1)
@@ -150,7 +150,7 @@ def nitrogen_electric_quadrupole_hamiltonian(self):
 
         """
         if self.isotope == 15:
-            h = 0
+            h = 0 # is this right? 
         else:
             #there must be a function in qutip,numpy or scipy for this?
             I_squared = qt.spin_Jx(self.nitrogen_spin)**2