Update the equation above the Bloch sphere in the measurement area to…

… match the measured state when the measurement occurs, #80
phetsims · Jan 16, 2025 · 1da4fcf · 1da4fcf
1 parent a9d2b8b
commit 1da4fcf
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Showing 4 changed files with 14 additions and 41 deletions.
diff --git a/js/bloch-sphere/model/BlochSphereModel.ts b/js/bloch-sphere/model/BlochSphereModel.ts
@@ -41,12 +41,6 @@ class BlochSphereModel implements TModel {
   public readonly singleMeasurementBlochSphere: ComplexBlochSphere;
   public readonly multiMeasurementBlochSpheres: ComplexBlochSphere[] = [];
 
-  // Coefficients of the state equation. They are derived from the Bloch Sphere representation on the multilink below.
-  // |psi> = upCoefficient |up> + downCoefficient * exp( i * phase * PI ) |down>
-  public readonly upCoefficientProperty: NumberProperty;
-  public readonly downCoefficientProperty: NumberProperty;
-  public readonly phaseFactorProperty: NumberProperty;
-
   // Selected State Direction
   public selectedStateDirectionProperty: Property<StateDirection>;
 
@@ -95,21 +89,6 @@ class BlochSphereModel implements TModel {
       } ) );
     } );
 
-    this.upCoefficientProperty = new NumberProperty( 0, {
-      tandem: providedOptions.tandem.createTandem( 'upCoefficientProperty' ),
-      phetioReadOnly: true
-    } );
-
-    this.downCoefficientProperty = new NumberProperty( 0, {
-      tandem: providedOptions.tandem.createTandem( 'downCoefficientProperty' ),
-      phetioReadOnly: true
-    } );
-
-    this.phaseFactorProperty = new NumberProperty( 0, {
-      tandem: providedOptions.tandem.createTandem( 'phaseFactorProperty' ),
-      phetioReadOnly: true
-    } );
-
     this.selectedStateDirectionProperty = new Property( StateDirection.Z_PLUS, {
       tandem: providedOptions.tandem.createTandem( 'selectedStateDirectionProperty' ),
       phetioValueType: EnumerationIO( StateDirection ),
@@ -173,25 +152,18 @@ class BlochSphereModel implements TModel {
     // measurement that is being made.
     this.timeToMeasurementProperty.link( () => this.resetCounts() );
 
-    // Update the coefficients, clear accumulated counts, and potentially change the selected preset state direction to
+    // Clear accumulated counts, and potentially change the selected preset state direction to
     // CUSTOM when the user changes the angles of the Bloch Sphere.
     Multilink.multilink(
       [
         this.preparationBlochSphere.polarAngleProperty,
         this.preparationBlochSphere.azimuthalAngleProperty
       ],
-      ( polarAngle, azimuthalAngle ) => {
-
-        // Update the coefficients of the state equation.
-        this.upCoefficientProperty.value = Math.cos( polarAngle / 2 );
-        this.downCoefficientProperty.value = Math.sin( polarAngle / 2 );
-        this.phaseFactorProperty.value = azimuthalAngle / Math.PI;
-
+      () => {
         // Clear the accumulated counts.
         this.resetCounts();
 
         if ( !selectingStateDirection ) {
-
           // Change the selected state to indicate that the user has moved away from the preset states.
           this.selectedStateDirectionProperty.value = StateDirection.CUSTOM;
         }

diff --git a/js/bloch-sphere/view/BlochSphereMeasurementArea.ts b/js/bloch-sphere/view/BlochSphereMeasurementArea.ts
@@ -41,7 +41,7 @@ export default class BlochSphereMeasurementArea extends Node {
 
   public constructor( model: BlochSphereModel, providedOptions: BlochSphereMeasurementAreaOptions ) {
 
-    const equationNode = new BlochSphereNumericalEquationNode( model, {
+    const equationNode = new BlochSphereNumericalEquationNode( model.singleMeasurementBlochSphere, {
       visibleProperty: model.isSingleMeasurementModeProperty,
       tandem: providedOptions.tandem.createTandem( 'equationNode' )
     } );

diff --git a/js/bloch-sphere/view/BlochSphereNumericalEquationNode.ts b/js/bloch-sphere/view/BlochSphereNumericalEquationNode.ts
@@ -13,9 +13,9 @@ import optionize, { EmptySelfOptions } from '../../../../phet-core/js/optionize.
 import WithRequired from '../../../../phet-core/js/types/WithRequired.js';
 import MathSymbolFont from '../../../../scenery-phet/js/MathSymbolFont.js';
 import { HBox, HBoxOptions, RichText } from '../../../../scenery/js/imports.js';
+import AbstractBlochSphere from '../../common/model/AbstractBlochSphere.js';
 import QuantumMeasurementConstants from '../../common/QuantumMeasurementConstants.js';
 import quantumMeasurement from '../../quantumMeasurement.js';
-import BlochSphereModel from '../model/BlochSphereModel.js';
 
 type SelfOptions = EmptySelfOptions;
 type BlochSphereNumericalEquationNodeOptions = SelfOptions & WithRequired<HBoxOptions, 'tandem'>;
@@ -29,18 +29,19 @@ const KET = QuantumMeasurementConstants.KET;
 
 export default class BlochSphereNumericalEquationNode extends HBox {
 
-  public constructor( model: BlochSphereModel, providedOptions?: BlochSphereNumericalEquationNodeOptions ) {
+  public constructor( blochSphere: AbstractBlochSphere, providedOptions?: BlochSphereNumericalEquationNodeOptions ) {
 
     const equationNode = new RichText( new DerivedStringProperty(
       [
-        model.upCoefficientProperty,
-        model.downCoefficientProperty,
-        model.phaseFactorProperty
+        blochSphere.polarAngleProperty,
+        blochSphere.azimuthalAngleProperty
       ],
-      ( upCoefficient: number, downCoefficient: number, phaseFactor: number ) => {
-        const upCoefficientString = Utils.toFixed( upCoefficient, 2 );
-        const downCoefficientString = Utils.toFixed( downCoefficient, 2 );
-        const azimuthalCoefficientString = Utils.toFixed( phaseFactor, 2 );
+      ( polarAngle, azimuthalAngle ) => {
+
+        // Update the coefficients of the state equation.
+        const upCoefficientString = Utils.toFixed( Math.cos( polarAngle / 2 ), 2 );
+        const downCoefficientString = Utils.toFixed( Math.sin( polarAngle / 2 ), 2 );
+        const azimuthalCoefficientString = Utils.toFixed( azimuthalAngle / Math.PI, 2 );
 
         return `|${PSI}⟩ = ${upCoefficientString}|${UP}${KET} + ${downCoefficientString}e<sup>i${azimuthalCoefficientString}${PI}</sup>|${DOWN}${KET}`;
       }

diff --git a/js/bloch-sphere/view/BlochSpherePreparationArea.ts b/js/bloch-sphere/view/BlochSpherePreparationArea.ts
@@ -95,7 +95,7 @@ export default class BlochSpherePreparationArea extends VBox {
         new Text( 'State to Prepare', { font: new PhetFont( { size: 20, weight: 'bolder' } ) } ),
         new BlochSphereSymbolicEquationNode(),
         new Panel(
-          new BlochSphereNumericalEquationNode( model ), {
+          new BlochSphereNumericalEquationNode( model.preparationBlochSphere ), {
             fill: '#aff',
             cornerRadius: 5,
             stroke: null,