Add layer fidelity experiment

qiskit_experiments/library/randomized_benchmarking/__init__.py

@@ -25,6 +25,7 @@
 
     StandardRB
     InterleavedRB
+    LayerFidelity
 
 
 Analysis
@@ -36,6 +37,7 @@
 
     RBAnalysis
     InterleavedRBAnalysis
+    LayerFidelityAnalysis
 
 Synthesis
 =========
@@ -61,3 +63,5 @@
 from .clifford_utils import CliffordUtils
 from .rb_utils import RBUtils
 from .clifford_synthesis import RBDefaultCliffordSynthesis
+from .layer_fidelity import LayerFidelity
+from .layer_fidelity_analysis import LayerFidelityAnalysis

qiskit_experiments/library/randomized_benchmarking/clifford_utils.py

@@ -46,6 +46,7 @@
 _valid_sparse_indices = _clifford_compose_2q_data["valid_sparse_indices"]
 # map a clifford number to the index of _CLIFFORD_COMPOSE_2Q_DENSE
 _clifford_num_to_dense_index = {idx: ii for ii, idx in enumerate(_valid_sparse_indices)}
+_CLIFFORD_TENSOR_1Q = np.load(f"{_DATA_FOLDER}/clifford_tensor_1q.npz")["table"]
 
 # Transpilation utilities
 def _transpile_clifford_circuit(
@@ -486,7 +487,11 @@ def inverse_1q(num: Integral) -> Integral:
 
 
 def num_from_1q_circuit(qc: QuantumCircuit) -> Integral:
-    """Convert a given 1-qubit Clifford circuit to the corresponding integer."""
+    """Convert a given 1-qubit Clifford circuit to the corresponding integer.
+
+    Note: The circuit must consist of gates in :const:`_CLIFF_SINGLE_GATE_MAP_1Q`,
+    RZGate, Delay and Barrier.
+    """
     num = 0
     for inst in qc:
         rhs = _num_from_1q_gate(op=inst.operation)
@@ -497,7 +502,7 @@ def num_from_1q_circuit(qc: QuantumCircuit) -> Integral:
 def _num_from_1q_gate(op: Instruction) -> int:
     """
     Convert a given 1-qubit clifford operation to the corresponding integer.
-    Note that supported operations are limited to ones in :const:`CLIFF_SINGLE_GATE_MAP_1Q` or Rz gate.
+    Note that supported operations are limited to ones in :const:`_CLIFF_SINGLE_GATE_MAP_1Q` or Rz gate.
 
     Args:
         op: operation to be converted.
@@ -556,7 +561,11 @@ def inverse_2q(num: Integral) -> Integral:
 
 
 def num_from_2q_circuit(qc: QuantumCircuit) -> Integral:
-    """Convert a given 2-qubit Clifford circuit to the corresponding integer."""
+    """Convert a given 2-qubit Clifford circuit to the corresponding integer.
+
+    Note: The circuit must consist of gates in :const:`_CLIFF_SINGLE_GATE_MAP_2Q`,
+    RZGate, Delay and Barrier.
+    """
     lhs = 0
     for rhs in _clifford_2q_nums_from_2q_circuit(qc):
         lhs = _CLIFFORD_COMPOSE_2Q_DENSE[lhs, _clifford_num_to_dense_index[rhs]]
@@ -568,7 +577,7 @@ def _num_from_2q_gate(
 ) -> int:
     """
     Convert a given 1-qubit clifford operation to the corresponding integer.
-    Note that supported operations are limited to ones in `CLIFF_SINGLE_GATE_MAP_2Q` or Rz gate.
+    Note that supported operations are limited to ones in `_CLIFF_SINGLE_GATE_MAP_2Q` or Rz gate.
 
     Args:
         op: operation of instruction to be converted.
@@ -730,3 +739,8 @@ def _layer_indices_from_num(num: Integral) -> Tuple[Integral, Integral, Integral
     idx1 = num % _NUM_LAYER_1
     idx0 = num // _NUM_LAYER_1
     return idx0, idx1, idx2
+
+
+def _tensor_1q_nums(first: Integral, second: Integral) -> Integral:
+    """Return the 2-qubit Clifford integer that is the tensor product of 1-qubit Cliffords."""
+    return _CLIFFORD_TENSOR_1Q[first, second]

qiskit_experiments/library/randomized_benchmarking/data/generate_clifford_data.py

@@ -59,7 +59,7 @@ def _hash_cliff(cliff):
 
 
 def gen_clifford_inverse_1q():
-    """Generate table data for integer 1Q Clifford inversion"""
+    """Generate data for integer 1Q Clifford inversion table"""
     invs = np.empty(NUM_CLIFFORD_1Q, dtype=int)
     for i, cliff_i in _CLIFF_1Q.items():
         invs[i] = _TO_INT_1Q[_hash_cliff(cliff_i.adjoint())]
@@ -68,7 +68,7 @@ def gen_clifford_inverse_1q():
 
 
 def gen_clifford_compose_1q():
-    """Generate table data for integer 1Q Clifford composition."""
+    """Generate data for integer 1Q Clifford composition table"""
     products = np.empty((NUM_CLIFFORD_1Q, NUM_CLIFFORD_1Q), dtype=int)
     for i, cliff_i in _CLIFF_1Q.items():
         for j, cliff_j in _CLIFF_1Q.items():
@@ -83,7 +83,7 @@ def gen_clifford_compose_1q():
 
 
 def gen_clifford_inverse_2q():
-    """Generate table data for integer 2Q Clifford inversion"""
+    """Generate data for integer 2Q Clifford inversion table"""
     invs = np.empty(NUM_CLIFFORD_2Q, dtype=int)
     for i, cliff_i in _CLIFF_2Q.items():
         invs[i] = _TO_INT_2Q[_hash_cliff(cliff_i.adjoint())]
@@ -191,6 +191,16 @@ def gen_cliff_single_2q_gate_map():
     return table
 
 
+def gen_clifford_tensor_1q():
+    """Generate data for 2Q integer Clifford table of the tensor product of 1Q integer Cliffords."""
+    products = np.empty((NUM_CLIFFORD_1Q, NUM_CLIFFORD_1Q), dtype=int)
+    for i, cliff_i in _CLIFF_1Q.items():
+        for j, cliff_j in _CLIFF_1Q.items():
+            cliff = cliff_i.tensor(cliff_j)
+            products[i, j] = _TO_INT_2Q[_hash_cliff(cliff)]
+    return products
+
+
 if __name__ == "__main__":
     if _CLIFF_SINGLE_GATE_MAP_1Q != gen_cliff_single_1q_gate_map():
         raise Exception(
@@ -212,3 +222,5 @@ def gen_cliff_single_2q_gate_map():
         table=_CLIFFORD_COMPOSE_2Q_DENSE,
         valid_sparse_indices=valid_sparse_indices,
     )
+
+    np.savez_compressed("clifford_tensor_1q.npz", table=gen_clifford_tensor_1q())