diff --git a/check_cirq_8054/get-total-memory b/check_cirq_8054/get-total-memory
new file mode 100755
index 000000000..aa9cce0e7
--- /dev/null
+++ b/check_cirq_8054/get-total-memory
@@ -0,0 +1,14 @@
+#!/usr/bin/gawk -f
+
+BEGIN { FS = "="; }
+
+/^snapshot=[0-9]+$/ {inrec = 1}
+inrec && /^time=[0-9]+/ {t = $2 * 1e-9}
+inrec && /^mem_heap_B/ {mem_heap_B = $2 + 0}
+inrec && /^mem_heap_extra_B/ {mem_heap_extra_B = $2 + 0}
+
+inrec && /^heap_tree/ {
+    print t, mem_heap_B + mem_heap_extra_B;
+    t = mem_heap_B = mem_heap_extra_B = "";
+    inrec = 0;
+}
diff --git a/check_cirq_8054/oom_qsim_simulation.py b/check_cirq_8054/oom_qsim_simulation.py
new file mode 100644
index 000000000..87b4aa12a
--- /dev/null
+++ b/check_cirq_8054/oom_qsim_simulation.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+
+"""Script to check for maximum number of qubits where QSimSimulator segfaults."""
+
+import gc
+import sys
+
+import cirq.testing
+
+import qsimcirq
+
+assert __name__ == "__main__"
+if len(sys.argv) != 2:
+    print(f"usage: {__file__} num_qubits")
+    sys.exit(0)
+
+nqubits = int(sys.argv[1])
+
+q = cirq.LineQubit.range(nqubits)
+m1 = cirq.Moment(cirq.H.on_each(q))
+m2 = cirq.Moment(cirq.CX(qi, qj) for qi, qj in zip(q[0::2], q[1::2]))
+m3 = cirq.Moment(cirq.measure(*q))
+c = cirq.Circuit(10 * [m1, m2, m3])
+
+my_sim = qsimcirq.QSimSimulator()
+
+gc.disable()
+gc.collect()
+
+state_vector = my_sim.simulate(program=c).state_vector()
+print(state_vector.shape, state_vector)
diff --git a/check_cirq_8054/qsim_simulation.py b/check_cirq_8054/qsim_simulation.py
new file mode 100644
index 000000000..3c620f090
--- /dev/null
+++ b/check_cirq_8054/qsim_simulation.py
@@ -0,0 +1,36 @@
+import gc
+
+import cirq.testing
+import numpy as np
+
+import qsimcirq
+
+nqubits = 20
+# nqubits = 24
+
+q = cirq.LineQubit.range(nqubits)
+m1 = cirq.Moment(cirq.H.on_each(q))
+m2 = cirq.Moment(cirq.CX(qi, qj) for qi, qj in zip(q[0::2], q[1::2]))
+m3 = cirq.Moment(cirq.measure(*q))
+c = cirq.Circuit(10 * [m1, m2, m3])
+
+# make reproducible initial_state
+rs = cirq.value.parse_random_state(8054)
+initial_state = cirq.testing.random_superposition(2**nqubits, random_state=rs).astype(
+    np.complex64
+)
+my_sim = qsimcirq.QSimSimulator()
+
+gc.disable()
+gc.collect()
+
+# burn CPU cycles for a few seconds
+for _ in range(50_000_000):
+    pass
+
+state_vector = my_sim.simulate(program=c, initial_state=initial_state).state_vector()
+print(state_vector.shape, state_vector)
+
+# burn CPU cycles for a few seconds
+for _ in range(50_000_000):
+    pass
diff --git a/check_cirq_8054/results/README.md b/check_cirq_8054/results/README.md
new file mode 100644
index 000000000..7ac763813
--- /dev/null
+++ b/check_cirq_8054/results/README.md
@@ -0,0 +1,42 @@
+# Check of memory in qsim simulation before and after cirq PR 8054
+
+2026-05-27
+
+Smallest number of qubits causing OOM crash, checked with
+`oom_qsim_simulation.py` on a Debian box with 65 GB of memory.
+
+- baseline qsim c5bc02394a and cirq f4c35b02090b - OOM for 34 qubits
+- patched qsim 7d05583a00e0 and cirq #8054 (bca9c5c617de) - OOM for 34 qubits
+
+# 2026-05-27 - RUN LIST ------------------------------------------------------
+
+Memory use during `qsim_simulation.py` was collected using
+```
+valgrind --tool=massif python qsim_simulation.py
+```
+The output massif.out.NNNNNN files were converted to memtotal.NNNNNN.dat
+using `get-total-memory` script.
+
+## baseline qsim and cirq ----------------------------------------------------
+
+### nqubits=20 (repeated to check reproducibility)
+
+- memtotal.733604.dat
+- memtotal.736557.dat
+
+### nqubits=24 (repeated to check reproducibility)
+
+- memtotal.737548.dat
+- memtotal.738662.dat
+
+## patched qsim and cirq -----------------------------------------------------
+
+### nqubits=20 (repeated to check reproducibility)
+
+- memtotal.742794.dat
+- memtotal.743107.dat
+
+### nqubits=24 (repeated to check reproducibility)
+
+- memtotal.743990.dat
+- memtotal.745873.dat
diff --git a/check_cirq_8054/results/memtotal.733604.dat b/check_cirq_8054/results/memtotal.733604.dat
new file mode 100644
index 000000000..02df9e3f2
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.733604.dat
@@ -0,0 +1,57 @@
+# time(s) total(B)
+0 0
+0.318674 1829576
+0.800413 1830656
+1.08539 1833280
+1.49621 3965600
+2.04109 11420768
+2.30147 13350360
+2.71264 17712696
+3.18717 19979776
+3.47974 23178960
+3.94386 23966192
+4.24774 22427040
+4.73715 26087592
+5.09345 21787608
+5.64853 34344200
+6.0532 23333832
+6.67339 23801272
+7.04263 24054344
+7.33646 26933312
+7.77634 26572128
+8.36293 31020344
+8.72959 27231152
+9.24349 30566016
+9.75678 29527336
+10.0368 31484856
+10.4515 32861584
+10.8521 34065888
+11.196 35819400
+11.5052 36376264
+12.1185 38817856
+12.5623 40904920
+12.8479 41389864
+13.4064 45973416
+13.7793 47525304
+14.251 46322464
+14.8548 46146888
+15.342 46148840
+15.9343 48427936
+16.4012 51152048
+16.9931 51333688
+17.316 54121000
+17.6824 54812296
+17.942 55830936
+18.3247 97230944
+20.4203 80317544
+44.9443 63538632
+45.2405 73033952
+45.7872 73034656
+46.152 73035184
+46.7043 73035976
+46.9648 73036416
+47.272 73036768
+47.5777 73037208
+47.8414 73037648
+48.1475 73038000
+48.4202 54819616
diff --git a/check_cirq_8054/results/memtotal.736557.dat b/check_cirq_8054/results/memtotal.736557.dat
new file mode 100644
index 000000000..011da7740
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.736557.dat
@@ -0,0 +1,68 @@
+# time(s) total(B)
+0 0
+0.236307 1829576
+0.647684 1830656
+0.901119 1831376
+1.16279 1832096
+1.62568 4855864
+2.04185 9461272
+2.42849 14207000
+2.81795 18432504
+3.1332 26787080
+3.35759 19030624
+3.67212 19919880
+3.88087 21932792
+4.32047 19697448
+4.59238 23449192
+4.92702 21260224
+5.38009 20740552
+5.6907 34344104
+5.93708 22432224
+6.32605 25918408
+6.56992 23932776
+6.91045 23969744
+7.34829 25118072
+7.78408 26126952
+8.07375 30650456
+8.4586 27037128
+8.84373 27238472
+9.32651 31547392
+9.80775 30132232
+10.225 31882384
+10.7115 33497720
+11.0001 34280976
+11.3337 36002080
+11.5094 36332816
+11.8853 39148072
+12.3438 38551040
+12.7539 40231696
+13.0397 40740888
+13.4487 45972408
+13.7677 45479008
+13.9993 45689144
+14.2996 46235768
+14.6829 46144856
+14.9561 46146808
+15.3351 46853200
+15.6352 48174776
+16.0247 49640680
+16.2574 51150992
+16.5575 50554072
+17.0139 53032160
+17.0688 53563424
+17.1723 54119576
+17.2426 55082016
+17.4184 55005768
+17.5942 55047960
+17.7699 55154488
+17.7983 55829528
+18.01 80314912
+18.0148 80314912
+18.1804 97228312
+23.2847 80314912
+48.5587 63536000
+48.7394 72163936
+48.9182 72164200
+49.0973 72164464
+49.2916 80326656
+49.4717 50396696
diff --git a/check_cirq_8054/results/memtotal.737548.dat b/check_cirq_8054/results/memtotal.737548.dat
new file mode 100644
index 000000000..bc739df6d
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.737548.dat
@@ -0,0 +1,99 @@
+# time(s) total(B)
+0 0
+0.24384 1829216
+0.563657 1829936
+0.813955 1831016
+1.0374 1833280
+1.30225 1839064
+1.70561 5389248
+1.99261 8696200
+2.35874 13350360
+2.64822 17147600
+2.86035 17388056
+3.14753 26787064
+3.44511 19185968
+3.9095 22048144
+4.13106 19868360
+4.49651 23122080
+4.84353 20408176
+5.04188 25635608
+5.38938 20717440
+5.7061 34344200
+6.00614 22499632
+6.30378 24823696
+6.60223 23307216
+6.80059 23870800
+7.12277 24077696
+7.44424 25003520
+7.60505 26300240
+7.92652 27032448
+8.32849 27879688
+8.56962 32657912
+8.89114 27523216
+9.29605 30264464
+9.6176 28986624
+9.86073 29245704
+10.1969 31991528
+10.5187 32886640
+10.8423 33753192
+11.0642 35095552
+11.4298 36270768
+11.7401 37901992
+12.1969 39385016
+12.6205 40904808
+13.0497 40608224
+13.2163 43593096
+13.6085 45439440
+13.8653 49127576
+14.1522 45892904
+14.5152 46145520
+14.9225 46146984
+15.1357 46147960
+15.3823 46178624
+15.5432 47147704
+15.704 47950408
+15.8649 48425552
+16.0267 49284560
+16.1023 49641512
+16.2521 50137968
+16.3066 50643288
+16.335 51151840
+16.496 50422248
+16.6568 50625192
+16.8176 51594632
+16.933 51679648
+16.9482 52507944
+17.0914 53033376
+17.1463 53564384
+17.2499 54120472
+17.3203 55082912
+17.4811 54936168
+17.6419 54878632
+17.8029 55084632
+17.8763 55830184
+20.4396 457805056
+20.5151 457805056
+23.0232 457806120
+23.1632 726376696
+31.0781 457805056
+58.5807 189367920
+59.6161 323858160
+59.8141 323858280
+60.7914 323858280
+60.9876 323858384
+61.9649 323858384
+62.1366 323858488
+63.1139 323858488
+64.1868 323858592
+65.3186 323858696
+65.5134 323858800
+66.4906 323858800
+67.5553 323858904
+67.7211 323859008
+68.6984 323859008
+68.9144 323859112
+69.8917 323859112
+70.074 323859056
+70.3125 592035208
+71.1325 457813440
+71.3126 50398104
diff --git a/check_cirq_8054/results/memtotal.738662.dat b/check_cirq_8054/results/memtotal.738662.dat
new file mode 100644
index 000000000..741d16b65
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.738662.dat
@@ -0,0 +1,93 @@
+# time(s) total(B)
+0 0
+0.241858 1829216
+0.536904 1829936
+0.894681 1831376
+1.27455 1839064
+1.52452 3959456
+1.85926 7373144
+2.07045 11420768
+2.33075 13350360
+2.62021 17147600
+3.02276 20972656
+3.26981 20011800
+3.60782 19686568
+3.9994 19947304
+4.43126 20900776
+4.7444 26079016
+5.00099 24878544
+5.30861 21661584
+5.51445 21796776
+5.83214 22214208
+6.09067 23660496
+6.50097 23262976
+6.75739 24200024
+7.06669 24054440
+7.47673 26595568
+7.80473 26572208
+8.0507 30377440
+8.37866 30944776
+8.78879 27357744
+9.03809 26869824
+9.36646 27613280
+9.61248 29491760
+9.94047 30378864
+10.3773 32756360
+10.7873 33739224
+11.2248 35818840
+11.5271 36351816
+11.7112 37901320
+12.0073 37163416
+12.2594 37482200
+12.5126 39146056
+12.7175 40066816
+13.0033 40273224
+13.4134 45563792
+13.8357 49126728
+14.0878 46245352
+14.4878 46145632
+14.8216 46146120
+15.041 46146608
+15.2749 46147584
+15.5079 46177760
+15.6922 47256600
+15.8763 48176712
+16.0605 48587120
+16.2278 49641032
+16.3791 50137528
+16.432 50642744
+16.4604 51151328
+16.6446 50560216
+16.8288 51104448
+17.013 51498128
+17.0585 51678992
+17.0737 52507288
+17.2169 53032368
+17.2718 53563488
+17.3753 54119592
+17.4456 55082048
+17.6298 54613072
+17.8141 55200336
+17.9984 55664752
+18.0014 55829448
+20.5648 457804288
+20.6403 457804288
+23.1484 457805352
+23.2883 726375928
+74.4273 457804288
+99.78 189367136
+100.815 323857024
+101.966 323857144
+103.039 323857264
+104.164 323857384
+104.362 323857504
+105.34 323857504
+106.412 323857624
+107.522 323857744
+108.655 323857864
+109.754 323857984
+110.857 323858104
+111.05 323858064
+111.288 592034424
+112.108 457816688
+112.292 49454784
diff --git a/check_cirq_8054/results/memtotal.742794.dat b/check_cirq_8054/results/memtotal.742794.dat
new file mode 100644
index 000000000..e052249e8
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.742794.dat
@@ -0,0 +1,69 @@
+# time(s) total(B)
+0 0
+0.247474 1829216
+0.540653 1829576
+0.786293 1830296
+1.06812 1831016
+1.55855 1839064
+1.92407 5965288
+2.24833 8696200
+2.61428 13350360
+2.90372 17147600
+3.4021 26787080
+3.72933 19672352
+4.08687 19494432
+4.29122 20214904
+4.72049 21273272
+5.22741 21488824
+5.56274 20457632
+5.96042 34344472
+6.29555 23498400
+6.51888 24248912
+6.85399 23578808
+7.13292 23859128
+7.41281 24236024
+7.80368 28179984
+8.02702 26961608
+8.36199 31016240
+8.80847 31750752
+9.25537 27998880
+9.59189 31490616
+9.81499 28774480
+10.1498 29713064
+10.4965 31882976
+10.8315 33037432
+11.3178 35095856
+11.683 36271008
+12.1628 39555792
+12.4179 38161304
+12.7047 38339768
+13.0165 39919040
+13.3021 40700312
+13.7166 45973656
+14.0356 45480320
+14.5473 46336720
+14.9329 46146776
+15.3997 46148728
+15.8492 46198344
+16.1366 48496040
+16.4234 48727888
+16.8018 51153208
+17.232 50724896
+17.3998 51681080
+17.4149 52509376
+17.558 53034648
+17.6129 53565976
+17.7165 54122128
+17.7868 55084616
+17.9912 54900216
+18.1956 55112600
+18.3425 55832128
+18.5543 80317512
+18.559 80317512
+18.7246 97230912
+22.0952 80317512
+46.6192 63538616
+46.838 72166488
+47.0868 72166840
+47.2923 72167032
+47.5067 50402640
diff --git a/check_cirq_8054/results/memtotal.743107.dat b/check_cirq_8054/results/memtotal.743107.dat
new file mode 100644
index 000000000..a9399c502
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.743107.dat
@@ -0,0 +1,71 @@
+# time(s) total(B)
+0 0
+0.274028 1829216
+0.85666 1831736
+1.20887 3650104
+1.62037 6885544
+1.95504 11949024
+2.37666 15808880
+2.81034 19454232
+3.11697 19797304
+3.50564 21092144
+3.89009 19605104
+4.21061 20099848
+4.53129 24973016
+4.94826 22676624
+5.25464 21229344
+5.48879 34344328
+5.79565 22544168
+6.10185 25778448
+6.40787 24768792
+6.71409 24296000
+6.95899 24743464
+7.38776 26356992
+7.63286 27613680
+7.8777 30548656
+8.25409 26850752
+8.53638 26515824
+8.91253 26874120
+9.38279 29034024
+9.75916 30615904
+10.0412 31967688
+10.512 33501808
+10.8464 35095392
+11.036 35819112
+11.4006 36497632
+11.6924 39555280
+11.9747 39309864
+12.2281 38919960
+12.5292 40089600
+12.8149 40273592
+13.2464 45972856
+13.6468 49127096
+13.8997 46254920
+14.3068 46145848
+14.5857 46147312
+14.8137 46148288
+15.1551 46284696
+15.5345 48212176
+15.7877 49278360
+16.0995 51153016
+16.4791 50680112
+16.6688 50874200
+16.6977 51680568
+16.7128 52508864
+16.8559 53034016
+16.9107 53565672
+17.0143 54121824
+17.0845 55084312
+17.2742 54681088
+17.4637 54932808
+17.6402 55832080
+17.8519 80317480
+17.8566 80317480
+18.0222 97230880
+32.5202 80317480
+57.7942 63538568
+58.012 72166680
+58.2058 72167032
+58.4462 72167296
+58.6358 50521248
+58.8254 9808016
diff --git a/check_cirq_8054/results/memtotal.743990.dat b/check_cirq_8054/results/memtotal.743990.dat
new file mode 100644
index 000000000..8651eeb5f
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.743990.dat
@@ -0,0 +1,69 @@
+# time(s) total(B)
+0 0
+0.323637 1829216
+0.627409 1830296
+1.0176 1831376
+1.34847 1832168
+1.63833 4506032
+2.05161 8743216
+2.34779 13008424
+2.66035 15706504
+2.95015 17670600
+3.42407 19143208
+3.88359 19792864
+4.41276 20929296
+4.92469 21975456
+5.28553 25116952
+5.75221 34344104
+6.16192 23648688
+6.44582 24049640
+6.93258 24337368
+7.21655 24392344
+7.62215 26014504
+8.02125 28631192
+8.25852 28289824
+8.73276 29854328
+9.09061 26869240
+9.44617 27938304
+9.68321 29380320
+10.039 30871032
+10.2877 31882384
+10.6433 33236744
+10.8804 33750680
+11.3001 35818840
+11.5947 36342872
+12.0751 37221496
+12.6672 40904248
+12.9479 41086848
+13.3633 45513992
+13.6736 46001640
+14.0741 45906352
+14.3985 46431056
+14.8151 46147328
+15.088 46148304
+15.5022 46899016
+15.8266 48215048
+16.3914 51153080
+16.7159 50657864
+17.1478 53034488
+17.7011 54918488
+17.9328 55831856
+20.4962 457806760
+20.5717 457806760
+23.0798 457807824
+23.2197 726378400
+32.4663 457806760
+59.2689 189369608
+60.3042 323859416
+61.427 323859536
+62.5246 323859656
+63.6921 323859776
+64.8145 323859896
+65.9257 323860016
+67.1287 323860136
+68.235 323860256
+69.3707 323860376
+70.5502 323860496
+70.7926 323779112
+71.7807 323592984
+72.0124 33151680
diff --git a/check_cirq_8054/results/memtotal.745873.dat b/check_cirq_8054/results/memtotal.745873.dat
new file mode 100644
index 000000000..24699b364
--- /dev/null
+++ b/check_cirq_8054/results/memtotal.745873.dat
@@ -0,0 +1,71 @@
+# time(s) total(B)
+0 0
+0.439876 1829576
+0.712697 1830296
+1.22238 1831736
+1.54455 3046264
+1.83998 5437624
+2.14288 8749640
+2.65572 14939648
+2.91956 17238600
+3.28229 26787080
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diff --git a/check_cirq_8054/results/plot_memory_use.png b/check_cirq_8054/results/plot_memory_use.png
new file mode 100644
index 000000000..6242d8a29
Binary files /dev/null and b/check_cirq_8054/results/plot_memory_use.png differ
diff --git a/check_cirq_8054/results/plot_memory_use.py b/check_cirq_8054/results/plot_memory_use.py
new file mode 100644
index 000000000..8ea0d951c
--- /dev/null
+++ b/check_cirq_8054/results/plot_memory_use.py
@@ -0,0 +1,39 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+memuse_files_q20 = [
+    # baseline qsim and cirq
+    "memtotal.733604.dat",
+    "memtotal.736557.dat",
+    # qsim and cirq with cirq-PR #8054
+    "memtotal.742794.dat",
+    "memtotal.743107.dat",
+]
+
+memuse_files_q24 = [
+    # baseline qsim and cirq
+    "memtotal.737548.dat",
+    "memtotal.738662.dat",
+    # qsim and cirq with cirq-PR #8054
+    "memtotal.743990.dat",
+    "memtotal.745873.dat",
+]
+
+t_mem_q20 = [col for f in memuse_files_q20 for col in np.loadtxt(f, unpack=True)]
+t_mem_q24 = [col for f in memuse_files_q24 for col in np.loadtxt(f, unpack=True)]
+
+fig, ax = plt.subplots(nrows=2)
+lines_q20 = ax[0].plot(*t_mem_q20)
+lines_q24 = ax[1].plot(*t_mem_q24)
+# blue dashed line with dot markers for baseline cirq
+plt.setp(lines_q20[0:2] + lines_q24[0:2], marker=".", linestyle=":", color="blue")
+# green solid line with x markers for runs with cirq-PR #8054
+plt.setp(lines_q20[2:] + lines_q24[2:], marker="x", markersize=7, color="green")
+# hide repeated runs
+plt.setp(lines_q20[1::2] + lines_q24[1::2], visible=False)
+plt.setp(ax, xlim=(0, 80), ylabel="total memory use (B)")
+ax[0].legend(lines_q20[0::2], ["baseline qsim", "qsim with cirq #8054"])
+ax[0].set_title("qsim_simulation.py, 20 qubits")
+ax[1].set_title("qsim_simulation.py, 24 qubits")
+ax[1].set_xlabel("process time (s)")
+plt.show()
diff --git a/qsimcirq/qsim_simulator.py b/qsimcirq/qsim_simulator.py
index 2b538167c..1163ecced 100644
--- a/qsimcirq/qsim_simulator.py
+++ b/qsimcirq/qsim_simulator.py
@@ -591,7 +591,9 @@ def simulate_sweep_iter(
             program, params, qubit_order, initial_state
         ):
             final_state = cirq.StateVectorSimulationState(
-                initial_state=state_vector, qubits=cirq_order
+                initial_state=state_vector,
+                qubits=cirq_order,
+                should_preserve_initial_state=False,
             )
             # create result for this parameter
             # TODO: We need to support measurements.