Add time evolution (controlled or uncontrolled) as a full circuit

qre/README.md

@@ -119,11 +119,11 @@ Calling more than one of these functions will generate an error.
 A variety of circuits can be generated and analyzed based on the time-evolution unitary operator.
 However, this section is still under development and currently has very limited options:
 
-- Textbook Phase Estimation: Setting `circuit.method` to "qualtran textbook" will embed the unitary
-  encoding of the Hamiltonian into a phase estimation circuit that uses the classic
+- Textbook Phase Estimation: Setting `circuit.method` to "QPE: qualtran textbook" will embed the
+  unitary encoding of the Hamiltonian into a phase estimation circuit that uses the classic
   "textbook" method (see, for example, Nielson and Chuang's "Quantum Computation and Quantum
   Information").
-- Qubitized Phase Estimation: Setting `circuit.method` to "pyliqtr qubitized" will embed the
+- Qubitized Phase Estimation: Setting `circuit.method` to "QPE: pyliqtr qubitized" will embed the
   unitary encoding of the Hamiltonian into a phase estimation circuit that uses pyLIQTR's qubitized
   phase estimation.  This uses only a single ancilla qubit for the phase, with multiple
   measurements to extract the necessary number of bits of information.  This method only works with

qre/config.py

@@ -33,11 +33,11 @@
 # phase estimation circuit
 
 if my_method == "Trotter":
-    circuit.method = "qualtran textbook"
+    circuit.method = "QPE: qualtran textbook"
     circuit.energy_error = 0.5 * energy_error
     circuit.probability_of_failure = 0.01
 elif my_method == "double-factorization":
-    circuit.method = "pyLIQTR qubitized"
+    circuit.method = "QPE: pyLIQTR qubitized"
     circuit.num_phase_qubits = 12
 else:
     raise ValueError(f"Invalid value for `my_method`: \"{my_method}\"")

qre/qre_analysis.py

@@ -1,6 +1,7 @@
 from qre_types import GeneralConfiguration, AnalysisConfiguration
 
 from pyLIQTR.utils.resource_analysis import estimate_resources as estimate_pyliqtr
+from qualtran.resource_counting import get_cost_value, QubitCount
 
 # -------------------------------------------------------------------------------------------------
 
@@ -28,11 +29,15 @@ def resource_estimation_pyliqtr(
     #       -- argument profile = False: estimate rotations as Clifford+T
     resources = estimate_pyliqtr(qpe_circuit)
 
-    return {
-            "Clifford_count" : resources["Clifford"],
-            "T_count"        : resources["T"],
-            "qubit_count"    : resources["LogicalQubits"]
-           }
+    resource_dict = {
+        "Clifford_count" : resources["Clifford"],
+        "T_count"        : resources["T"],
+        }
+    if "LogicalQubits" in resources:
+        resource_dict["qubit_count"] = resources["LogicalQubits"]
+    else:
+        get_cost_value(qpe_circuit, QubitCount())
+    return resource_dict
 
 # -------------------------------------------------------------------------------------------------
 

qre/qre_circuit.py

@@ -119,6 +119,28 @@ def build_qpe_pyliqtr_qubitized(
 
 # -------------------------------------------------------------------------------------------------
 
+def build_time_evolution(
+        config_general: GeneralConfiguration,
+        config_qpe: QPEConfiguration,
+        unitary):
+
+    config_general.log_verbose("Build a time evolution circuit.")
+
+    return unitary
+
+# -------------------------------------------------------------------------------------------------
+
+def build_controlled_time_evolution(
+        config_general: GeneralConfiguration,
+        config_qpe: QPEConfiguration,
+        unitary):
+
+    config_general.log_verbose("Build a singly-controlled time evolution circuit.")
+
+    return unitary.controlled()
+
+# -------------------------------------------------------------------------------------------------
+
 def build_qpe_circuit(
         config_general: GeneralConfiguration,
         config_qpe: QPEConfiguration,
@@ -127,13 +149,17 @@ def build_qpe_circuit(
 
     config_general.log("Beginning to construct quantum phase estimation circuit.")
 
-    if config_qpe.method.lower() in ("qualtran textbook",):
+    if config_qpe.method.lower() in ("qpe: qualtran textbook",):
         return build_qpe_qualtran_textbook(config_general, config_qpe, unitary, P0)
-    elif config_qpe.method.lower() in ("qualtran qubitization",):
+    elif config_qpe.method.lower() in ("qpe: qualtran qubitization",):
         # TODO: This may be more specialized (for LCU only?), but I'm not yet sure of the details.
         raise NotImplementedError()
-    elif config_qpe.method.lower() in ("pyliqtr qubitized",):
+    elif config_qpe.method.lower() in ("qpe: pyliqtr qubitized",):
         return build_qpe_pyliqtr_qubitized(config_general, config_qpe, unitary)
+    elif config_qpe.method.lower() in ("time evolution",):
+        return build_time_evolution(config_general, config_qpe, unitary)
+    elif config_qpe.method.lower() in ("controlled time evolution",):
+        return build_controlled_time_evolution(config_general, config_qpe, unitary)
     else:
         raise ValueError(f"Invalid QPE circuit method \"{config_qpe.method}\".")