From dc232115ac6004d95329def5d0a38c253dfa615d Mon Sep 17 00:00:00 2001
From: Unai Corzo <corzounai@gmail.com>
Date: Wed, 3 Nov 2021 20:49:26 +0100
Subject: [PATCH 1/2] Define cirq.ISWAP_INV

---
 cirq-core/cirq/__init__.py                       |  1 +
 cirq-core/cirq/ops/pauli_string_test.py          |  2 +-
 cirq-core/cirq/ops/swap_gates.py                 | 16 ++++++++++++++++
 .../serialization/common_serializers_test.py     |  2 +-
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/cirq-core/cirq/__init__.py b/cirq-core/cirq/__init__.py
index 9085d27f959..8301077db6f 100644
--- a/cirq-core/cirq/__init__.py
+++ b/cirq-core/cirq/__init__.py
@@ -227,6 +227,7 @@
     IdentityGate,
     InterchangeableQubitsGate,
     ISWAP,
+    ISWAP_INV,
     ISwapPowGate,
     KrausChannel,
     LinearCombinationOfGates,
diff --git a/cirq-core/cirq/ops/pauli_string_test.py b/cirq-core/cirq/ops/pauli_string_test.py
index 83e2f140656..a6e8dd7ebab 100644
--- a/cirq-core/cirq/ops/pauli_string_test.py
+++ b/cirq-core/cirq/ops/pauli_string_test.py
@@ -1492,7 +1492,7 @@ def _decompose_(self, qubits):
         cirq.CNOT,
         cirq.CZ,
         cirq.ISWAP,
-        cirq.ISWAP ** -1,
+        cirq.ISWAP_INV,
         cirq.SWAP,
         cirq.XX ** 0.5,
         cirq.YY ** 0.5,
diff --git a/cirq-core/cirq/ops/swap_gates.py b/cirq-core/cirq/ops/swap_gates.py
index fd464d6cd6b..7e8f7c6554c 100644
--- a/cirq-core/cirq/ops/swap_gates.py
+++ b/cirq-core/cirq/ops/swap_gates.py
@@ -16,6 +16,7 @@
 This module creates Gate instances for the following gates:
     SWAP: the swap gate.
     ISWAP: a swap gate with a phase on the swapped subspace.
+    ISWAP_INV: inverse of the ISWAP gate.
     SQRT_ISWAP: square root of the ISWAP gate.
     SQRT_ISWAP_INV: inverse square root of the ISWAP gate.
 
@@ -338,6 +339,21 @@ def riswap(rads: value.TParamVal) -> ISwapPowGate:
     """,
 )
 
+ISWAP_INV = ISwapPowGate(exponent=-1)
+document(
+    ISWAP_INV,
+    """The inverse of iswap gate.
+
+    Matrix:
+    ```
+        [[1, 0,  0,  0],
+         [0, 0,  -i, 0],
+         [0, -i, 0,  0],
+         [0, 0,  0,  1]]
+    ```
+    """,
+)
+
 SQRT_ISWAP = ISwapPowGate(exponent=0.5)
 document(
     SQRT_ISWAP,
diff --git a/cirq-google/cirq_google/serialization/common_serializers_test.py b/cirq-google/cirq_google/serialization/common_serializers_test.py
index 6a7651366fa..c4b42cee61a 100644
--- a/cirq-google/cirq_google/serialization/common_serializers_test.py
+++ b/cirq-google/cirq_google/serialization/common_serializers_test.py
@@ -551,7 +551,7 @@ def test_wait_gate_multi_qubit():
         (cirq.ISWAP ** 0.5, -np.pi / 4, 0),
         (cirq.ISWAP ** -0.5, np.pi / 4, 0),
         (cirq.ISWAP ** 1.0, -np.pi / 2, 0),
-        (cirq.ISWAP ** -1.0, np.pi / 2, 0),
+        (cirq.ISWAP_INV, np.pi / 2, 0),
         (cirq.ISWAP ** 0.0, 0, 0),
         (cirq.CZ, 0, np.pi),
         (cirq.CZ ** -1.0, 0, np.pi),

From 1860bb252d2bf3f37ad3f64d6cf43e13526bdc5d Mon Sep 17 00:00:00 2001
From: Unai Corzo <corzounai@gmail.com>
Date: Wed, 3 Nov 2021 21:01:27 +0100
Subject: [PATCH 2/2] Add ISWAP_INV to cirq.ops

---
 cirq-core/cirq/ops/__init__.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cirq-core/cirq/ops/__init__.py b/cirq-core/cirq/ops/__init__.py
index 0b4041e5641..f9584f5f59a 100644
--- a/cirq-core/cirq/ops/__init__.py
+++ b/cirq-core/cirq/ops/__init__.py
@@ -267,6 +267,7 @@
 
 from cirq.ops.swap_gates import (
     ISWAP,
+    ISWAP_INV,
     ISwapPowGate,
     riswap,
     SQRT_ISWAP,